Mercurial > cpython-lru_cache-weakref

annotate Doc/c-api/typeobj.rst @ 79691:05c8928362ee

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Merge __next__ method link fixes with 3.3.
author Ezio Melotti <ezio.melotti@gmail.com>
date Fri, 12 Oct 2012 13:46:37 +0300
parents da2aaced21bd
children a381721299a3 3f994367a979
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 .. highlightlang:: c
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2
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3 .. _type-structs:
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4
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5 Type Objects
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6 ============
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7
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8 Perhaps one of the most important structures of the Python object system is the
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9 structure that defines a new type: the :c:type:`PyTypeObject` structure. Type
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10 objects can be handled using any of the :c:func:`PyObject_\*` or
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11 :c:func:`PyType_\*` functions, but do not offer much that's interesting to most
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12 Python applications. These objects are fundamental to how objects behave, so
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13 they are very important to the interpreter itself and to any extension module
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14 that implements new types.
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15
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16 Type objects are fairly large compared to most of the standard types. The reason
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17 for the size is that each type object stores a large number of values, mostly C
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18 function pointers, each of which implements a small part of the type's
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19 functionality. The fields of the type object are examined in detail in this
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20 section. The fields will be described in the order in which they occur in the
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21 structure.
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22
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23 Typedefs: unaryfunc, binaryfunc, ternaryfunc, inquiry, intargfunc,
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24 intintargfunc, intobjargproc, intintobjargproc, objobjargproc, destructor,
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25 freefunc, printfunc, getattrfunc, getattrofunc, setattrfunc, setattrofunc,
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26 reprfunc, hashfunc
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27
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28 The structure definition for :c:type:`PyTypeObject` can be found in
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29 :file:`Include/object.h`. For convenience of reference, this repeats the
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30 definition found there:
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31
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32 .. literalinclude:: ../includes/typestruct.h
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33
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34
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35 The type object structure extends the :c:type:`PyVarObject` structure. The
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36 :attr:`ob_size` field is used for dynamic types (created by :func:`type_new`,
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37 usually called from a class statement). Note that :c:data:`PyType_Type` (the
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38 metatype) initializes :attr:`tp_itemsize`, which means that its instances (i.e.
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39 type objects) *must* have the :attr:`ob_size` field.
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40
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41
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42 .. c:member:: PyObject* PyObject._ob_next
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43 PyObject* PyObject._ob_prev
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44
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45 These fields are only present when the macro ``Py_TRACE_REFS`` is defined.
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46 Their initialization to *NULL* is taken care of by the ``PyObject_HEAD_INIT``
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47 macro. For statically allocated objects, these fields always remain *NULL*.
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48 For dynamically allocated objects, these two fields are used to link the object
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49 into a doubly-linked list of *all* live objects on the heap. This could be used
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50 for various debugging purposes; currently the only use is to print the objects
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51 that are still alive at the end of a run when the environment variable
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52 :envvar:`PYTHONDUMPREFS` is set.
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53
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54 These fields are not inherited by subtypes.
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55
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56
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57 .. c:member:: Py_ssize_t PyObject.ob_refcnt
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58
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59 This is the type object's reference count, initialized to ``1`` by the
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60 ``PyObject_HEAD_INIT`` macro. Note that for statically allocated type objects,
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61 the type's instances (objects whose :attr:`ob_type` points back to the type) do
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62 *not* count as references. But for dynamically allocated type objects, the
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63 instances *do* count as references.
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64
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65 This field is not inherited by subtypes.
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66
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67
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68 .. c:member:: PyTypeObject* PyObject.ob_type
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69
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70 This is the type's type, in other words its metatype. It is initialized by the
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71 argument to the ``PyObject_HEAD_INIT`` macro, and its value should normally be
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72 ``&PyType_Type``. However, for dynamically loadable extension modules that must
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73 be usable on Windows (at least), the compiler complains that this is not a valid
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74 initializer. Therefore, the convention is to pass *NULL* to the
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75 ``PyObject_HEAD_INIT`` macro and to initialize this field explicitly at the
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76 start of the module's initialization function, before doing anything else. This
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77 is typically done like this::
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78
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79 Foo_Type.ob_type = &PyType_Type;
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80
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81 This should be done before any instances of the type are created.
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82 :c:func:`PyType_Ready` checks if :attr:`ob_type` is *NULL*, and if so,
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83 initializes it to the :attr:`ob_type` field of the base class.
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84 :c:func:`PyType_Ready` will not change this field if it is non-zero.
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85
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86 This field is inherited by subtypes.
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87
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88
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89 .. c:member:: Py_ssize_t PyVarObject.ob_size
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90
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91 For statically allocated type objects, this should be initialized to zero. For
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92 dynamically allocated type objects, this field has a special internal meaning.
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93
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94 This field is not inherited by subtypes.
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95
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96
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97 .. c:member:: char* PyTypeObject.tp_name
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98
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99 Pointer to a NUL-terminated string containing the name of the type. For types
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100 that are accessible as module globals, the string should be the full module
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101 name, followed by a dot, followed by the type name; for built-in types, it
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102 should be just the type name. If the module is a submodule of a package, the
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103 full package name is part of the full module name. For example, a type named
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104 :class:`T` defined in module :mod:`M` in subpackage :mod:`Q` in package :mod:`P`
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105 should have the :attr:`tp_name` initializer ``"P.Q.M.T"``.
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106
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107 For dynamically allocated type objects, this should just be the type name, and
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108 the module name explicitly stored in the type dict as the value for key
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109 ``'__module__'``.
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110
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111 For statically allocated type objects, the tp_name field should contain a dot.
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112 Everything before the last dot is made accessible as the :attr:`__module__`
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113 attribute, and everything after the last dot is made accessible as the
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114 :attr:`__name__` attribute.
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115
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116 If no dot is present, the entire :attr:`tp_name` field is made accessible as the
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117 :attr:`__name__` attribute, and the :attr:`__module__` attribute is undefined
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118 (unless explicitly set in the dictionary, as explained above). This means your
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119 type will be impossible to pickle.
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120
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121 This field is not inherited by subtypes.
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122
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123
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124 .. c:member:: Py_ssize_t PyTypeObject.tp_basicsize
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125 Py_ssize_t PyTypeObject.tp_itemsize
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126
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127 These fields allow calculating the size in bytes of instances of the type.
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128
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129 There are two kinds of types: types with fixed-length instances have a zero
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130 :attr:`tp_itemsize` field, types with variable-length instances have a non-zero
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131 :attr:`tp_itemsize` field. For a type with fixed-length instances, all
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132 instances have the same size, given in :attr:`tp_basicsize`.
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133
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134 For a type with variable-length instances, the instances must have an
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135 :attr:`ob_size` field, and the instance size is :attr:`tp_basicsize` plus N
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136 times :attr:`tp_itemsize`, where N is the "length" of the object. The value of
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137 N is typically stored in the instance's :attr:`ob_size` field. There are
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138 exceptions: for example, ints use a negative :attr:`ob_size` to indicate a
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139 negative number, and N is ``abs(ob_size)`` there. Also, the presence of an
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140 :attr:`ob_size` field in the instance layout doesn't mean that the instance
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141 structure is variable-length (for example, the structure for the list type has
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142 fixed-length instances, yet those instances have a meaningful :attr:`ob_size`
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143 field).
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144
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145 The basic size includes the fields in the instance declared by the macro
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146 :c:macro:`PyObject_HEAD` or :c:macro:`PyObject_VAR_HEAD` (whichever is used to
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147 declare the instance struct) and this in turn includes the :attr:`_ob_prev` and
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148 :attr:`_ob_next` fields if they are present. This means that the only correct
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149 way to get an initializer for the :attr:`tp_basicsize` is to use the
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150 ``sizeof`` operator on the struct used to declare the instance layout.
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151 The basic size does not include the GC header size.
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152
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153 These fields are inherited separately by subtypes. If the base type has a
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154 non-zero :attr:`tp_itemsize`, it is generally not safe to set
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155 :attr:`tp_itemsize` to a different non-zero value in a subtype (though this
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156 depends on the implementation of the base type).
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157
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158 A note about alignment: if the variable items require a particular alignment,
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159 this should be taken care of by the value of :attr:`tp_basicsize`. Example:
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160 suppose a type implements an array of ``double``. :attr:`tp_itemsize` is
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161 ``sizeof(double)``. It is the programmer's responsibility that
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162 :attr:`tp_basicsize` is a multiple of ``sizeof(double)`` (assuming this is the
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163 alignment requirement for ``double``).
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164
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165
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166 .. c:member:: destructor PyTypeObject.tp_dealloc
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167
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168 A pointer to the instance destructor function. This function must be defined
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169 unless the type guarantees that its instances will never be deallocated (as is
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170 the case for the singletons ``None`` and ``Ellipsis``).
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171
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172 The destructor function is called by the :c:func:`Py_DECREF` and
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173 :c:func:`Py_XDECREF` macros when the new reference count is zero. At this point,
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174 the instance is still in existence, but there are no references to it. The
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175 destructor function should free all references which the instance owns, free all
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176 memory buffers owned by the instance (using the freeing function corresponding
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177 to the allocation function used to allocate the buffer), and finally (as its
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178 last action) call the type's :attr:`tp_free` function. If the type is not
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179 subtypable (doesn't have the :const:`Py_TPFLAGS_BASETYPE` flag bit set), it is
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180 permissible to call the object deallocator directly instead of via
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181 :attr:`tp_free`. The object deallocator should be the one used to allocate the
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182 instance; this is normally :c:func:`PyObject_Del` if the instance was allocated
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183 using :c:func:`PyObject_New` or :c:func:`PyObject_VarNew`, or
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184 :c:func:`PyObject_GC_Del` if the instance was allocated using
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185 :c:func:`PyObject_GC_New` or :c:func:`PyObject_GC_NewVar`.
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186
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187 This field is inherited by subtypes.
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188
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189
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190 .. c:member:: printfunc PyTypeObject.tp_print
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191
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192 An optional pointer to the instance print function.
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193
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194 The print function is only called when the instance is printed to a *real* file;
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195 when it is printed to a pseudo-file (like a :class:`StringIO` instance), the
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196 instance's :attr:`tp_repr` or :attr:`tp_str` function is called to convert it to
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197 a string. These are also called when the type's :attr:`tp_print` field is
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198 *NULL*. A type should never implement :attr:`tp_print` in a way that produces
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199 different output than :attr:`tp_repr` or :attr:`tp_str` would.
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200
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201 The print function is called with the same signature as :c:func:`PyObject_Print`:
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202 ``int tp_print(PyObject *self, FILE *file, int flags)``. The *self* argument is
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203 the instance to be printed. The *file* argument is the stdio file to which it
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204 is to be printed. The *flags* argument is composed of flag bits. The only flag
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205 bit currently defined is :const:`Py_PRINT_RAW`. When the :const:`Py_PRINT_RAW`
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206 flag bit is set, the instance should be printed the same way as :attr:`tp_str`
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207 would format it; when the :const:`Py_PRINT_RAW` flag bit is clear, the instance
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208 should be printed the same was as :attr:`tp_repr` would format it. It should
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209 return ``-1`` and set an exception condition when an error occurred during the
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210 comparison.
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211
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212 It is possible that the :attr:`tp_print` field will be deprecated. In any case,
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213 it is recommended not to define :attr:`tp_print`, but instead to rely on
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214 :attr:`tp_repr` and :attr:`tp_str` for printing.
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215
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216 This field is inherited by subtypes.
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217
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218
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219 .. c:member:: getattrfunc PyTypeObject.tp_getattr
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220
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221 An optional pointer to the get-attribute-string function.
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222
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223 This field is deprecated. When it is defined, it should point to a function
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224 that acts the same as the :attr:`tp_getattro` function, but taking a C string
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225 instead of a Python string object to give the attribute name. The signature is
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226 the same as for :c:func:`PyObject_GetAttrString`.
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227
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228 This field is inherited by subtypes together with :attr:`tp_getattro`: a subtype
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229 inherits both :attr:`tp_getattr` and :attr:`tp_getattro` from its base type when
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230 the subtype's :attr:`tp_getattr` and :attr:`tp_getattro` are both *NULL*.
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231
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232
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233 .. c:member:: setattrfunc PyTypeObject.tp_setattr
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234
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235 An optional pointer to the set-attribute-string function.
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236
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237 This field is deprecated. When it is defined, it should point to a function
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238 that acts the same as the :attr:`tp_setattro` function, but taking a C string
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239 instead of a Python string object to give the attribute name. The signature is
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240 the same as for :c:func:`PyObject_SetAttrString`.
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241
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242 This field is inherited by subtypes together with :attr:`tp_setattro`: a subtype
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243 inherits both :attr:`tp_setattr` and :attr:`tp_setattro` from its base type when
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244 the subtype's :attr:`tp_setattr` and :attr:`tp_setattro` are both *NULL*.
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245
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246
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247 .. c:member:: void* PyTypeObject.tp_reserved
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248
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249 Reserved slot, formerly known as tp_compare.
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250
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251
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252 .. c:member:: reprfunc PyTypeObject.tp_repr
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253
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254 .. index:: builtin: repr
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255
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256 An optional pointer to a function that implements the built-in function
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257 :func:`repr`.
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258
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259 The signature is the same as for :c:func:`PyObject_Repr`; it must return a string
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260 or a Unicode object. Ideally, this function should return a string that, when
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261 passed to :func:`eval`, given a suitable environment, returns an object with the
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262 same value. If this is not feasible, it should return a string starting with
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263 ``'<'`` and ending with ``'>'`` from which both the type and the value of the
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264 object can be deduced.
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265
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266 When this field is not set, a string of the form ``<%s object at %p>`` is
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267 returned, where ``%s`` is replaced by the type name, and ``%p`` by the object's
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268 memory address.
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269
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270 This field is inherited by subtypes.
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271
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272 .. c:member:: PyNumberMethods* tp_as_number
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273
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Georg Brandl <georg@python.org>
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274 Pointer to an additional structure that contains fields relevant only to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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275 objects which implement the number protocol. These fields are documented in
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Georg Brandl <georg@python.org>
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276 :ref:`number-structs`.
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diff changeset
277
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278 The :attr:`tp_as_number` field is not inherited, but the contained fields are
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279 inherited individually.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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diff changeset
280
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Georg Brandl <georg@python.org>
parents:
diff changeset
281
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282 .. c:member:: PySequenceMethods* tp_as_sequence
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283
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Georg Brandl <georg@python.org>
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284 Pointer to an additional structure that contains fields relevant only to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
285 objects which implement the sequence protocol. These fields are documented
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Georg Brandl <georg@python.org>
parents:
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286 in :ref:`sequence-structs`.
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Georg Brandl <georg@python.org>
parents:
diff changeset
287
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Georg Brandl <georg@python.org>
parents:
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288 The :attr:`tp_as_sequence` field is not inherited, but the contained fields
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289 are inherited individually.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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diff changeset
290
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Georg Brandl <georg@python.org>
parents:
diff changeset
291
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292 .. c:member:: PyMappingMethods* tp_as_mapping
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293
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Georg Brandl <georg@python.org>
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294 Pointer to an additional structure that contains fields relevant only to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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295 objects which implement the mapping protocol. These fields are documented in
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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296 :ref:`mapping-structs`.
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297
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Georg Brandl <georg@python.org>
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298 The :attr:`tp_as_mapping` field is not inherited, but the contained fields
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299 are inherited individually.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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diff changeset
300
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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diff changeset
301
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302 .. c:member:: hashfunc PyTypeObject.tp_hash
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303
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
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304 .. index:: builtin: hash
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Georg Brandl <georg@python.org>
parents:
diff changeset
305
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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306 An optional pointer to a function that implements the built-in function
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Georg Brandl <georg@python.org>
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307 :func:`hash`.
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308
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Benjamin Peterson <benjamin@python.org>
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309 The signature is the same as for :c:func:`PyObject_Hash`; it must return a
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Benjamin Peterson <benjamin@python.org>
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310 value of the type Py_hash_t. The value ``-1`` should not be returned as a
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Benjamin Peterson <benjamin@python.org>
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311 normal return value; when an error occurs during the computation of the hash
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312 value, the function should set an exception and return ``-1``.
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313
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314 This field can be set explicitly to :c:func:`PyObject_HashNotImplemented` to
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315 block inheritance of the hash method from a parent type. This is interpreted
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316 as the equivalent of ``__hash__ = None`` at the Python level, causing
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Nick Coghlan <ncoghlan@gmail.com>
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317 ``isinstance(o, collections.Hashable)`` to correctly return ``False``. Note
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318 that the converse is also true - setting ``__hash__ = None`` on a class at
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319 the Python level will result in the ``tp_hash`` slot being set to
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320 :c:func:`PyObject_HashNotImplemented`.
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Nick Coghlan <ncoghlan@gmail.com>
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diff changeset
321
51279
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
parents: 50822
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322 When this field is not set, an attempt to take the hash of the
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
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323 object raises :exc:`TypeError`.
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324
51279
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325 This field is inherited by subtypes together with
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
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326 :attr:`tp_richcompare`: a subtype inherits both of
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
parents: 50822
diff changeset
327 :attr:`tp_richcompare` and :attr:`tp_hash`, when the subtype's
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
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328 :attr:`tp_richcompare` and :attr:`tp_hash` are both *NULL*.
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329
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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diff changeset
330
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331 .. c:member:: ternaryfunc PyTypeObject.tp_call
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332
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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333 An optional pointer to a function that implements calling the object. This
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Georg Brandl <georg@python.org>
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334 should be *NULL* if the object is not callable. The signature is the same as
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335 for :c:func:`PyObject_Call`.
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
336
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
337 This field is inherited by subtypes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
338
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
339
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340 .. c:member:: reprfunc PyTypeObject.tp_str
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341
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
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342 An optional pointer to a function that implements the built-in operation
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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343 :func:`str`. (Note that :class:`str` is a type now, and :func:`str` calls the
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344 constructor for that type. This constructor calls :c:func:`PyObject_Str` to do
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
345 the actual work, and :c:func:`PyObject_Str` will call this handler.)
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346
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347 The signature is the same as for :c:func:`PyObject_Str`; it must return a string
44812
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Georg Brandl <georg@python.org>
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348 or a Unicode object. This function should return a "friendly" string
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
349 representation of the object, as this is the representation that will be used,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
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diff changeset
350 among other things, by the :func:`print` function.
1e8b9e7c34ce Split C API docs in Py3k branch.
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parents:
diff changeset
351
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352 When this field is not set, :c:func:`PyObject_Repr` is called to return a string
44812
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353 representation.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
354
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
355 This field is inherited by subtypes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
356
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
357
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358 .. c:member:: getattrofunc PyTypeObject.tp_getattro
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Georg Brandl <georg@python.org>
parents:
diff changeset
359
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
360 An optional pointer to the get-attribute function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
361
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362 The signature is the same as for :c:func:`PyObject_GetAttr`. It is usually
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
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363 convenient to set this field to :c:func:`PyObject_GenericGetAttr`, which
44812
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Georg Brandl <georg@python.org>
parents:
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364 implements the normal way of looking for object attributes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
365
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
366 This field is inherited by subtypes together with :attr:`tp_getattr`: a subtype
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
367 inherits both :attr:`tp_getattr` and :attr:`tp_getattro` from its base type when
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
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368 the subtype's :attr:`tp_getattr` and :attr:`tp_getattro` are both *NULL*.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
369
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
370
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Georg Brandl <georg@python.org>
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diff changeset
371 .. c:member:: setattrofunc PyTypeObject.tp_setattro
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Georg Brandl <georg@python.org>
parents:
diff changeset
372
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
373 An optional pointer to the set-attribute function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
374
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375 The signature is the same as for :c:func:`PyObject_SetAttr`. It is usually
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
376 convenient to set this field to :c:func:`PyObject_GenericSetAttr`, which
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
377 implements the normal way of setting object attributes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
378
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
379 This field is inherited by subtypes together with :attr:`tp_setattr`: a subtype
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
380 inherits both :attr:`tp_setattr` and :attr:`tp_setattro` from its base type when
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
381 the subtype's :attr:`tp_setattr` and :attr:`tp_setattro` are both *NULL*.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
382
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
383
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Georg Brandl <georg@python.org>
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diff changeset
384 .. c:member:: PyBufferProcs* PyTypeObject.tp_as_buffer
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
385
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
386 Pointer to an additional structure that contains fields relevant only to objects
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
387 which implement the buffer interface. These fields are documented in
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
388 :ref:`buffer-structs`.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
389
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
390 The :attr:`tp_as_buffer` field is not inherited, but the contained fields are
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
391 inherited individually.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
392
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
393
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Georg Brandl <georg@python.org>
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diff changeset
394 .. c:member:: long PyTypeObject.tp_flags
44812
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parents:
diff changeset
395
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
396 This field is a bit mask of various flags. Some flags indicate variant
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
397 semantics for certain situations; others are used to indicate that certain
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
398 fields in the type object (or in the extension structures referenced via
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
399 :attr:`tp_as_number`, :attr:`tp_as_sequence`, :attr:`tp_as_mapping`, and
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
400 :attr:`tp_as_buffer`) that were historically not always present are valid; if
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
401 such a flag bit is clear, the type fields it guards must not be accessed and
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
402 must be considered to have a zero or *NULL* value instead.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
403
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
404 Inheritance of this field is complicated. Most flag bits are inherited
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
405 individually, i.e. if the base type has a flag bit set, the subtype inherits
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
406 this flag bit. The flag bits that pertain to extension structures are strictly
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
407 inherited if the extension structure is inherited, i.e. the base type's value of
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
408 the flag bit is copied into the subtype together with a pointer to the extension
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409 structure. The :const:`Py_TPFLAGS_HAVE_GC` flag bit is inherited together with
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410 the :attr:`tp_traverse` and :attr:`tp_clear` fields, i.e. if the
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411 :const:`Py_TPFLAGS_HAVE_GC` flag bit is clear in the subtype and the
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412 :attr:`tp_traverse` and :attr:`tp_clear` fields in the subtype exist and have
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413 *NULL* values.
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414
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415 The following bit masks are currently defined; these can be ORed together using
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416 the ``|`` operator to form the value of the :attr:`tp_flags` field. The macro
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417 :c:func:`PyType_HasFeature` takes a type and a flags value, *tp* and *f*, and
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418 checks whether ``tp->tp_flags & f`` is non-zero.
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419
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420
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421 .. data:: Py_TPFLAGS_HEAPTYPE
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422
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423 This bit is set when the type object itself is allocated on the heap. In this
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424 case, the :attr:`ob_type` field of its instances is considered a reference to
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425 the type, and the type object is INCREF'ed when a new instance is created, and
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426 DECREF'ed when an instance is destroyed (this does not apply to instances of
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427 subtypes; only the type referenced by the instance's ob_type gets INCREF'ed or
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428 DECREF'ed).
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429
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430
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431 .. data:: Py_TPFLAGS_BASETYPE
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432
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433 This bit is set when the type can be used as the base type of another type. If
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434 this bit is clear, the type cannot be subtyped (similar to a "final" class in
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435 Java).
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436
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437
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438 .. data:: Py_TPFLAGS_READY
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439
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440 This bit is set when the type object has been fully initialized by
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441 :c:func:`PyType_Ready`.
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442
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443
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444 .. data:: Py_TPFLAGS_READYING
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445
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446 This bit is set while :c:func:`PyType_Ready` is in the process of initializing
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447 the type object.
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448
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449
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450 .. data:: Py_TPFLAGS_HAVE_GC
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451
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452 This bit is set when the object supports garbage collection. If this bit
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453 is set, instances must be created using :c:func:`PyObject_GC_New` and
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454 destroyed using :c:func:`PyObject_GC_Del`. More information in section
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455 :ref:`supporting-cycle-detection`. This bit also implies that the
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456 GC-related fields :attr:`tp_traverse` and :attr:`tp_clear` are present in
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457 the type object.
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458
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459
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460 .. data:: Py_TPFLAGS_DEFAULT
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461
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462 This is a bitmask of all the bits that pertain to the existence of certain
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463 fields in the type object and its extension structures. Currently, it includes
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464 the following bits: :const:`Py_TPFLAGS_HAVE_STACKLESS_EXTENSION`,
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465 :const:`Py_TPFLAGS_HAVE_VERSION_TAG`.
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466
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467
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468 .. c:member:: char* PyTypeObject.tp_doc
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469
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470 An optional pointer to a NUL-terminated C string giving the docstring for this
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471 type object. This is exposed as the :attr:`__doc__` attribute on the type and
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472 instances of the type.
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473
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474 This field is *not* inherited by subtypes.
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475
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476
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477 .. c:member:: traverseproc PyTypeObject.tp_traverse
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478
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479 An optional pointer to a traversal function for the garbage collector. This is
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480 only used if the :const:`Py_TPFLAGS_HAVE_GC` flag bit is set. More information
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481 about Python's garbage collection scheme can be found in section
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482 :ref:`supporting-cycle-detection`.
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483
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484 The :attr:`tp_traverse` pointer is used by the garbage collector to detect
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485 reference cycles. A typical implementation of a :attr:`tp_traverse` function
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486 simply calls :c:func:`Py_VISIT` on each of the instance's members that are Python
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487 objects. For example, this is function :c:func:`local_traverse` from the
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488 :mod:`_thread` extension module::
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489
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490 static int
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491 local_traverse(localobject *self, visitproc visit, void *arg)
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492 {
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493 Py_VISIT(self->args);
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494 Py_VISIT(self->kw);
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495 Py_VISIT(self->dict);
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496 return 0;
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497 }
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498
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499 Note that :c:func:`Py_VISIT` is called only on those members that can participate
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500 in reference cycles. Although there is also a ``self->key`` member, it can only
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501 be *NULL* or a Python string and therefore cannot be part of a reference cycle.
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502
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503 On the other hand, even if you know a member can never be part of a cycle, as a
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504 debugging aid you may want to visit it anyway just so the :mod:`gc` module's
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505 :func:`get_referents` function will include it.
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506
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507 Note that :c:func:`Py_VISIT` requires the *visit* and *arg* parameters to
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508 :c:func:`local_traverse` to have these specific names; don't name them just
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509 anything.
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510
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511 This field is inherited by subtypes together with :attr:`tp_clear` and the
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512 :const:`Py_TPFLAGS_HAVE_GC` flag bit: the flag bit, :attr:`tp_traverse`, and
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513 :attr:`tp_clear` are all inherited from the base type if they are all zero in
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514 the subtype.
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515
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516
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517 .. c:member:: inquiry PyTypeObject.tp_clear
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518
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519 An optional pointer to a clear function for the garbage collector. This is only
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520 used if the :const:`Py_TPFLAGS_HAVE_GC` flag bit is set.
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521
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522 The :attr:`tp_clear` member function is used to break reference cycles in cyclic
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523 garbage detected by the garbage collector. Taken together, all :attr:`tp_clear`
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524 functions in the system must combine to break all reference cycles. This is
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525 subtle, and if in any doubt supply a :attr:`tp_clear` function. For example,
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526 the tuple type does not implement a :attr:`tp_clear` function, because it's
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527 possible to prove that no reference cycle can be composed entirely of tuples.
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528 Therefore the :attr:`tp_clear` functions of other types must be sufficient to
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529 break any cycle containing a tuple. This isn't immediately obvious, and there's
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530 rarely a good reason to avoid implementing :attr:`tp_clear`.
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531
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532 Implementations of :attr:`tp_clear` should drop the instance's references to
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533 those of its members that may be Python objects, and set its pointers to those
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534 members to *NULL*, as in the following example::
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535
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536 static int
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537 local_clear(localobject *self)
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538 {
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539 Py_CLEAR(self->key);
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540 Py_CLEAR(self->args);
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541 Py_CLEAR(self->kw);
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542 Py_CLEAR(self->dict);
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543 return 0;
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544 }
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545
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546 The :c:func:`Py_CLEAR` macro should be used, because clearing references is
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diff changeset
547 delicate: the reference to the contained object must not be decremented until
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
548 after the pointer to the contained object is set to *NULL*. This is because
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
549 decrementing the reference count may cause the contained object to become trash,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
550 triggering a chain of reclamation activity that may include invoking arbitrary
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
551 Python code (due to finalizers, or weakref callbacks, associated with the
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
552 contained object). If it's possible for such code to reference *self* again,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
553 it's important that the pointer to the contained object be *NULL* at that time,
1e8b9e7c34ce Split C API docs in Py3k branch.
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parents:
diff changeset
554 so that *self* knows the contained object can no longer be used. The
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555 :c:func:`Py_CLEAR` macro performs the operations in a safe order.
44812
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diff changeset
556
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
557 Because the goal of :attr:`tp_clear` functions is to break reference cycles,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
558 it's not necessary to clear contained objects like Python strings or Python
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
559 integers, which can't participate in reference cycles. On the other hand, it may
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
560 be convenient to clear all contained Python objects, and write the type's
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
561 :attr:`tp_dealloc` function to invoke :attr:`tp_clear`.
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parents:
diff changeset
562
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
563 More information about Python's garbage collection scheme can be found in
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
564 section :ref:`supporting-cycle-detection`.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
565
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
566 This field is inherited by subtypes together with :attr:`tp_traverse` and the
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parents:
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567 :const:`Py_TPFLAGS_HAVE_GC` flag bit: the flag bit, :attr:`tp_traverse`, and
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parents:
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568 :attr:`tp_clear` are all inherited from the base type if they are all zero in
46963
03b1233bf5fe Remove many "versionchanged" items that didn't use the official markup,
Georg Brandl <georg@python.org>
parents: 46610
diff changeset
569 the subtype.
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
570
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
571
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572 .. c:member:: richcmpfunc PyTypeObject.tp_richcompare
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parents:
diff changeset
573
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
574 An optional pointer to the rich comparison function, whose signature is
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
575 ``PyObject *tp_richcompare(PyObject *a, PyObject *b, int op)``.
44812
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parents:
diff changeset
576
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
577 The function should return the result of the comparison (usually ``Py_True``
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parents: 44812
diff changeset
578 or ``Py_False``). If the comparison is undefined, it must return
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
579 ``Py_NotImplemented``, if another error occurred it must return ``NULL`` and
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
580 set an exception condition.
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
581
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
582 .. note::
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
583
ed33da2e74e7 Merged revisions 60143-60149 via svnmerge from
Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
584 If you want to implement a type for which only a limited set of
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
585 comparisons makes sense (e.g. ``==`` and ``!=``, but not ``<`` and
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
586 friends), directly raise :exc:`TypeError` in the rich comparison function.
44812
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diff changeset
587
51279
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
parents: 50822
diff changeset
588 This field is inherited by subtypes together with :attr:`tp_hash`:
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
parents: 50822
diff changeset
589 a subtype inherits :attr:`tp_richcompare` and :attr:`tp_hash` when
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
parents: 50822
diff changeset
590 the subtype's :attr:`tp_richcompare` and :attr:`tp_hash` are both
786c1278572c Issue #1717, continued: Doc fixes and other cleanup related
Mark Dickinson <dickinsm@gmail.com>
parents: 50822
diff changeset
591 *NULL*.
44812
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parents:
diff changeset
592
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
593 The following constants are defined to be used as the third argument for
65137
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Georg Brandl <georg@python.org>
parents: 59617
diff changeset
594 :attr:`tp_richcompare` and for :c:func:`PyObject_RichCompare`:
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
595
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
596 +----------------+------------+
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parents:
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597 | Constant | Comparison |
1e8b9e7c34ce Split C API docs in Py3k branch.
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parents:
diff changeset
598 +================+============+
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Georg Brandl <georg@python.org>
parents:
diff changeset
599 | :const:`Py_LT` | ``<`` |
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
600 +----------------+------------+
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parents:
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601 | :const:`Py_LE` | ``<=`` |
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
602 +----------------+------------+
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parents:
diff changeset
603 | :const:`Py_EQ` | ``==`` |
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
604 +----------------+------------+
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
605 | :const:`Py_NE` | ``!=`` |
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
606 +----------------+------------+
1e8b9e7c34ce Split C API docs in Py3k branch.
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parents:
diff changeset
607 | :const:`Py_GT` | ``>`` |
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
608 +----------------+------------+
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
609 | :const:`Py_GE` | ``>=`` |
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
610 +----------------+------------+
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
611
44834
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Christian Heimes <christian@cheimes.de>
parents: 44812
diff changeset
612
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613 .. c:member:: long PyTypeObject.tp_weaklistoffset
44812
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diff changeset
614
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
615 If the instances of this type are weakly referenceable, this field is greater
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
616 than zero and contains the offset in the instance structure of the weak
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
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617 reference list head (ignoring the GC header, if present); this offset is used by
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diff changeset
618 :c:func:`PyObject_ClearWeakRefs` and the :c:func:`PyWeakref_\*` functions. The
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
619 instance structure needs to include a field of type :c:type:`PyObject\*` which is
44812
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parents:
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620 initialized to *NULL*.
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Georg Brandl <georg@python.org>
parents:
diff changeset
621
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Georg Brandl <georg@python.org>
parents:
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622 Do not confuse this field with :attr:`tp_weaklist`; that is the list head for
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
623 weak references to the type object itself.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
624
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
625 This field is inherited by subtypes, but see the rules listed below. A subtype
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
626 may override this offset; this means that the subtype uses a different weak
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
627 reference list head than the base type. Since the list head is always found via
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
628 :attr:`tp_weaklistoffset`, this should not be a problem.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
629
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
630 When a type defined by a class statement has no :attr:`__slots__` declaration,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
631 and none of its base types are weakly referenceable, the type is made weakly
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
632 referenceable by adding a weak reference list head slot to the instance layout
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
633 and setting the :attr:`tp_weaklistoffset` of that slot's offset.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
634
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
635 When a type's :attr:`__slots__` declaration contains a slot named
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
636 :attr:`__weakref__`, that slot becomes the weak reference list head for
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
637 instances of the type, and the slot's offset is stored in the type's
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
638 :attr:`tp_weaklistoffset`.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
639
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
640 When a type's :attr:`__slots__` declaration does not contain a slot named
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
641 :attr:`__weakref__`, the type inherits its :attr:`tp_weaklistoffset` from its
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
642 base type.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
643
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Georg Brandl <georg@python.org>
parents: 59617
diff changeset
644 .. c:member:: getiterfunc PyTypeObject.tp_iter
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
645
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
646 An optional pointer to a function that returns an iterator for the object. Its
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
647 presence normally signals that the instances of this type are iterable (although
46347
cd08184637c5 #2567: remove new-style/old-style class docs.
Georg Brandl <georg@python.org>
parents: 45435
diff changeset
648 sequences may be iterable without this function).
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
649
65137
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Georg Brandl <georg@python.org>
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diff changeset
650 This function has the same signature as :c:func:`PyObject_GetIter`.
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
651
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
652 This field is inherited by subtypes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
653
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
654
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Georg Brandl <georg@python.org>
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diff changeset
655 .. c:member:: iternextfunc PyTypeObject.tp_iternext
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
656
46610
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parents: 46347
diff changeset
657 An optional pointer to a function that returns the next item in an iterator.
014535719668 Merged revisions 62602 via svnmerge from
Georg Brandl <georg@python.org>
parents: 46347
diff changeset
658 When the iterator is exhausted, it must return *NULL*; a :exc:`StopIteration`
014535719668 Merged revisions 62602 via svnmerge from
Georg Brandl <georg@python.org>
parents: 46347
diff changeset
659 exception may or may not be set. When another error occurs, it must return
014535719668 Merged revisions 62602 via svnmerge from
Georg Brandl <georg@python.org>
parents: 46347
diff changeset
660 *NULL* too. Its presence signals that the instances of this type are
014535719668 Merged revisions 62602 via svnmerge from
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diff changeset
661 iterators.
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
662
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
663 Iterator types should also define the :attr:`tp_iter` function, and that
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
664 function should return the iterator instance itself (not a new iterator
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
665 instance).
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
666
65137
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Georg Brandl <georg@python.org>
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diff changeset
667 This function has the same signature as :c:func:`PyIter_Next`.
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
668
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
669 This field is inherited by subtypes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
670
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
671
65137
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diff changeset
672 .. c:member:: struct PyMethodDef* PyTypeObject.tp_methods
44812
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parents:
diff changeset
673
65137
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Georg Brandl <georg@python.org>
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diff changeset
674 An optional pointer to a static *NULL*-terminated array of :c:type:`PyMethodDef`
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
675 structures, declaring regular methods of this type.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
676
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
677 For each entry in the array, an entry is added to the type's dictionary (see
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
678 :attr:`tp_dict` below) containing a method descriptor.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
679
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
680 This field is not inherited by subtypes (methods are inherited through a
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
681 different mechanism).
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
682
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
683
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Georg Brandl <georg@python.org>
parents: 59617
diff changeset
684 .. c:member:: struct PyMemberDef* PyTypeObject.tp_members
44812
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Georg Brandl <georg@python.org>
parents:
diff changeset
685
65137
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Georg Brandl <georg@python.org>
parents: 59617
diff changeset
686 An optional pointer to a static *NULL*-terminated array of :c:type:`PyMemberDef`
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
687 structures, declaring regular data members (fields or slots) of instances of
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
688 this type.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
689
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
690 For each entry in the array, an entry is added to the type's dictionary (see
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
691 :attr:`tp_dict` below) containing a member descriptor.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
692
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
693 This field is not inherited by subtypes (members are inherited through a
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
694 different mechanism).
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
695
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
696
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
697 .. c:member:: struct PyGetSetDef* PyTypeObject.tp_getset
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
698
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
699 An optional pointer to a static *NULL*-terminated array of :c:type:`PyGetSetDef`
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
700 structures, declaring computed attributes of instances of this type.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
701
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
702 For each entry in the array, an entry is added to the type's dictionary (see
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
703 :attr:`tp_dict` below) containing a getset descriptor.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
704
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
705 This field is not inherited by subtypes (computed attributes are inherited
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
706 through a different mechanism).
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
707
68008
c79665fb267a Merged revisions 87101,87146,87156,87172,87175,87371,87378,87522-87524,87526-87528,87530-87536,87581 via svnmerge from
Georg Brandl <georg@python.org>
parents: 66860
diff changeset
708 .. XXX belongs elsewhere
c79665fb267a Merged revisions 87101,87146,87156,87172,87175,87371,87378,87522-87524,87526-87528,87530-87536,87581 via svnmerge from
Georg Brandl <georg@python.org>
parents: 66860
diff changeset
709
c79665fb267a Merged revisions 87101,87146,87156,87172,87175,87371,87378,87522-87524,87526-87528,87530-87536,87581 via svnmerge from
Georg Brandl <georg@python.org>
parents: 66860
diff changeset
710 Docs for PyGetSetDef::
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
711
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
712 typedef PyObject *(*getter)(PyObject *, void *);
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
713 typedef int (*setter)(PyObject *, PyObject *, void *);
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
714
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
715 typedef struct PyGetSetDef {
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
716 char *name; /* attribute name */
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
717 getter get; /* C function to get the attribute */
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
718 setter set; /* C function to set the attribute */
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
719 char *doc; /* optional doc string */
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
720 void *closure; /* optional additional data for getter and setter */
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
721 } PyGetSetDef;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
722
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
723
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
724 .. c:member:: PyTypeObject* PyTypeObject.tp_base
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
725
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
726 An optional pointer to a base type from which type properties are inherited. At
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
727 this level, only single inheritance is supported; multiple inheritance require
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
728 dynamically creating a type object by calling the metatype.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
729
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
730 This field is not inherited by subtypes (obviously), but it defaults to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
731 ``&PyBaseObject_Type`` (which to Python programmers is known as the type
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
732 :class:`object`).
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
733
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
734
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
735 .. c:member:: PyObject* PyTypeObject.tp_dict
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
736
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
737 The type's dictionary is stored here by :c:func:`PyType_Ready`.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
738
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
739 This field should normally be initialized to *NULL* before PyType_Ready is
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
740 called; it may also be initialized to a dictionary containing initial attributes
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
741 for the type. Once :c:func:`PyType_Ready` has initialized the type, extra
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
742 attributes for the type may be added to this dictionary only if they don't
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
743 correspond to overloaded operations (like :meth:`__add__`).
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
744
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
745 This field is not inherited by subtypes (though the attributes defined in here
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
746 are inherited through a different mechanism).
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
747
71791
6ef65516fd7a note mutating tp_dict is bad (closes #12719)
Benjamin Peterson <benjamin@python.org>
parents: 68257
diff changeset
748 .. warning::
6ef65516fd7a note mutating tp_dict is bad (closes #12719)
Benjamin Peterson <benjamin@python.org>
parents: 68257
diff changeset
749
6ef65516fd7a note mutating tp_dict is bad (closes #12719)
Benjamin Peterson <benjamin@python.org>
parents: 68257
diff changeset
750 It is not safe to use :c:func:`PyDict_SetItem` on or otherwise modify
6ef65516fd7a note mutating tp_dict is bad (closes #12719)
Benjamin Peterson <benjamin@python.org>
parents: 68257
diff changeset
751 :attr:`tp_dict` with the dictionary C-API.
6ef65516fd7a note mutating tp_dict is bad (closes #12719)
Benjamin Peterson <benjamin@python.org>
parents: 68257
diff changeset
752
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
753
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
754 .. c:member:: descrgetfunc PyTypeObject.tp_descr_get
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
755
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
756 An optional pointer to a "descriptor get" function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
757
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
758 The function signature is ::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
759
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
760 PyObject * tp_descr_get(PyObject *self, PyObject *obj, PyObject *type);
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
761
68008
c79665fb267a Merged revisions 87101,87146,87156,87172,87175,87371,87378,87522-87524,87526-87528,87530-87536,87581 via svnmerge from
Georg Brandl <georg@python.org>
parents: 66860
diff changeset
762 .. XXX explain.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
763
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
764 This field is inherited by subtypes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
765
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
766
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
767 .. c:member:: descrsetfunc PyTypeObject.tp_descr_set
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
768
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
769 An optional pointer to a "descriptor set" function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
770
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
771 The function signature is ::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
772
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
773 int tp_descr_set(PyObject *self, PyObject *obj, PyObject *value);
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
774
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
775 This field is inherited by subtypes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
776
68008
c79665fb267a Merged revisions 87101,87146,87156,87172,87175,87371,87378,87522-87524,87526-87528,87530-87536,87581 via svnmerge from
Georg Brandl <georg@python.org>
parents: 66860
diff changeset
777 .. XXX explain.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
778
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
779
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
780 .. c:member:: long PyTypeObject.tp_dictoffset
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
781
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
782 If the instances of this type have a dictionary containing instance variables,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
783 this field is non-zero and contains the offset in the instances of the type of
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
784 the instance variable dictionary; this offset is used by
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
785 :c:func:`PyObject_GenericGetAttr`.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
786
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
787 Do not confuse this field with :attr:`tp_dict`; that is the dictionary for
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
788 attributes of the type object itself.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
789
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
790 If the value of this field is greater than zero, it specifies the offset from
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
791 the start of the instance structure. If the value is less than zero, it
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
792 specifies the offset from the *end* of the instance structure. A negative
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
793 offset is more expensive to use, and should only be used when the instance
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
794 structure contains a variable-length part. This is used for example to add an
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
795 instance variable dictionary to subtypes of :class:`str` or :class:`tuple`. Note
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
796 that the :attr:`tp_basicsize` field should account for the dictionary added to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
797 the end in that case, even though the dictionary is not included in the basic
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
798 object layout. On a system with a pointer size of 4 bytes,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
799 :attr:`tp_dictoffset` should be set to ``-4`` to indicate that the dictionary is
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
800 at the very end of the structure.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
801
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
802 The real dictionary offset in an instance can be computed from a negative
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
803 :attr:`tp_dictoffset` as follows::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
804
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
805 dictoffset = tp_basicsize + abs(ob_size)*tp_itemsize + tp_dictoffset
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
806 if dictoffset is not aligned on sizeof(void*):
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
807 round up to sizeof(void*)
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
808
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
809 where :attr:`tp_basicsize`, :attr:`tp_itemsize` and :attr:`tp_dictoffset` are
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
810 taken from the type object, and :attr:`ob_size` is taken from the instance. The
50822
7bc8e2eed690 Fix a few more references to long integers in the docs.
Mark Dickinson <dickinsm@gmail.com>
parents: 50821
diff changeset
811 absolute value is taken because ints use the sign of :attr:`ob_size` to
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
812 store the sign of the number. (There's never a need to do this calculation
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
813 yourself; it is done for you by :c:func:`_PyObject_GetDictPtr`.)
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
814
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
815 This field is inherited by subtypes, but see the rules listed below. A subtype
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
816 may override this offset; this means that the subtype instances store the
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
817 dictionary at a difference offset than the base type. Since the dictionary is
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
818 always found via :attr:`tp_dictoffset`, this should not be a problem.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
819
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
820 When a type defined by a class statement has no :attr:`__slots__` declaration,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
821 and none of its base types has an instance variable dictionary, a dictionary
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
822 slot is added to the instance layout and the :attr:`tp_dictoffset` is set to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
823 that slot's offset.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
824
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
825 When a type defined by a class statement has a :attr:`__slots__` declaration,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
826 the type inherits its :attr:`tp_dictoffset` from its base type.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
827
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
828 (Adding a slot named :attr:`__dict__` to the :attr:`__slots__` declaration does
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
829 not have the expected effect, it just causes confusion. Maybe this should be
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
830 added as a feature just like :attr:`__weakref__` though.)
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
831
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
832
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
833 .. c:member:: initproc PyTypeObject.tp_init
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
834
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
835 An optional pointer to an instance initialization function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
836
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
837 This function corresponds to the :meth:`__init__` method of classes. Like
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
838 :meth:`__init__`, it is possible to create an instance without calling
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
839 :meth:`__init__`, and it is possible to reinitialize an instance by calling its
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
840 :meth:`__init__` method again.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
841
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
842 The function signature is ::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
843
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
844 int tp_init(PyObject *self, PyObject *args, PyObject *kwds)
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
845
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
846 The self argument is the instance to be initialized; the *args* and *kwds*
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
847 arguments represent positional and keyword arguments of the call to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
848 :meth:`__init__`.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
849
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
850 The :attr:`tp_init` function, if not *NULL*, is called when an instance is
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
851 created normally by calling its type, after the type's :attr:`tp_new` function
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
852 has returned an instance of the type. If the :attr:`tp_new` function returns an
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
853 instance of some other type that is not a subtype of the original type, no
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
854 :attr:`tp_init` function is called; if :attr:`tp_new` returns an instance of a
46963
03b1233bf5fe Remove many "versionchanged" items that didn't use the official markup,
Georg Brandl <georg@python.org>
parents: 46610
diff changeset
855 subtype of the original type, the subtype's :attr:`tp_init` is called.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
856
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
857 This field is inherited by subtypes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
858
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
859
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
860 .. c:member:: allocfunc PyTypeObject.tp_alloc
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
861
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
862 An optional pointer to an instance allocation function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
863
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
864 The function signature is ::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
865
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
866 PyObject *tp_alloc(PyTypeObject *self, Py_ssize_t nitems)
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
867
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
868 The purpose of this function is to separate memory allocation from memory
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
869 initialization. It should return a pointer to a block of memory of adequate
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
870 length for the instance, suitably aligned, and initialized to zeros, but with
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
871 :attr:`ob_refcnt` set to ``1`` and :attr:`ob_type` set to the type argument. If
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
872 the type's :attr:`tp_itemsize` is non-zero, the object's :attr:`ob_size` field
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
873 should be initialized to *nitems* and the length of the allocated memory block
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
874 should be ``tp_basicsize + nitems*tp_itemsize``, rounded up to a multiple of
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
875 ``sizeof(void*)``; otherwise, *nitems* is not used and the length of the block
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
876 should be :attr:`tp_basicsize`.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
877
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
878 Do not use this function to do any other instance initialization, not even to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
879 allocate additional memory; that should be done by :attr:`tp_new`.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
880
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
881 This field is inherited by static subtypes, but not by dynamic subtypes
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
882 (subtypes created by a class statement); in the latter, this field is always set
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
883 to :c:func:`PyType_GenericAlloc`, to force a standard heap allocation strategy.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
884 That is also the recommended value for statically defined types.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
885
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
886
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
887 .. c:member:: newfunc PyTypeObject.tp_new
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
888
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
889 An optional pointer to an instance creation function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
890
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
891 If this function is *NULL* for a particular type, that type cannot be called to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
892 create new instances; presumably there is some other way to create instances,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
893 like a factory function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
894
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
895 The function signature is ::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
896
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
897 PyObject *tp_new(PyTypeObject *subtype, PyObject *args, PyObject *kwds)
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
898
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
899 The subtype argument is the type of the object being created; the *args* and
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
900 *kwds* arguments represent positional and keyword arguments of the call to the
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
901 type. Note that subtype doesn't have to equal the type whose :attr:`tp_new`
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
902 function is called; it may be a subtype of that type (but not an unrelated
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
903 type).
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
904
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
905 The :attr:`tp_new` function should call ``subtype->tp_alloc(subtype, nitems)``
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
906 to allocate space for the object, and then do only as much further
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
907 initialization as is absolutely necessary. Initialization that can safely be
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
908 ignored or repeated should be placed in the :attr:`tp_init` handler. A good
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
909 rule of thumb is that for immutable types, all initialization should take place
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
910 in :attr:`tp_new`, while for mutable types, most initialization should be
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
911 deferred to :attr:`tp_init`.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
912
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
913 This field is inherited by subtypes, except it is not inherited by static types
46963
03b1233bf5fe Remove many "versionchanged" items that didn't use the official markup,
Georg Brandl <georg@python.org>
parents: 46610
diff changeset
914 whose :attr:`tp_base` is *NULL* or ``&PyBaseObject_Type``.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
915
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
916
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
917 .. c:member:: destructor PyTypeObject.tp_free
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
918
46963
03b1233bf5fe Remove many "versionchanged" items that didn't use the official markup,
Georg Brandl <georg@python.org>
parents: 46610
diff changeset
919 An optional pointer to an instance deallocation function. Its signature is
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
920 :c:type:`freefunc`::
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
921
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
922 void tp_free(void *)
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
923
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
924 An initializer that is compatible with this signature is :c:func:`PyObject_Free`.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
925
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
926 This field is inherited by static subtypes, but not by dynamic subtypes
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
927 (subtypes created by a class statement); in the latter, this field is set to a
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
928 deallocator suitable to match :c:func:`PyType_GenericAlloc` and the value of the
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
929 :const:`Py_TPFLAGS_HAVE_GC` flag bit.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
930
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
931
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
932 .. c:member:: inquiry PyTypeObject.tp_is_gc
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
933
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
934 An optional pointer to a function called by the garbage collector.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
935
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
936 The garbage collector needs to know whether a particular object is collectible
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
937 or not. Normally, it is sufficient to look at the object's type's
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
938 :attr:`tp_flags` field, and check the :const:`Py_TPFLAGS_HAVE_GC` flag bit. But
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
939 some types have a mixture of statically and dynamically allocated instances, and
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
940 the statically allocated instances are not collectible. Such types should
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
941 define this function; it should return ``1`` for a collectible instance, and
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
942 ``0`` for a non-collectible instance. The signature is ::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
943
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
944 int tp_is_gc(PyObject *self)
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
945
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
946 (The only example of this are types themselves. The metatype,
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
947 :c:data:`PyType_Type`, defines this function to distinguish between statically
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
948 and dynamically allocated types.)
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
949
46963
03b1233bf5fe Remove many "versionchanged" items that didn't use the official markup,
Georg Brandl <georg@python.org>
parents: 46610
diff changeset
950 This field is inherited by subtypes.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
951
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
952
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
953 .. c:member:: PyObject* PyTypeObject.tp_bases
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
954
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
955 Tuple of base types.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
956
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
957 This is set for types created by a class statement. It should be *NULL* for
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
958 statically defined types.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
959
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
960 This field is not inherited.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
961
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
962
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
963 .. c:member:: PyObject* PyTypeObject.tp_mro
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
964
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
965 Tuple containing the expanded set of base types, starting with the type itself
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
966 and ending with :class:`object`, in Method Resolution Order.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
967
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
968 This field is not inherited; it is calculated fresh by :c:func:`PyType_Ready`.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
969
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
970
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
971 .. c:member:: PyObject* PyTypeObject.tp_cache
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
972
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
973 Unused. Not inherited. Internal use only.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
974
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
975
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
976 .. c:member:: PyObject* PyTypeObject.tp_subclasses
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
977
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
978 List of weak references to subclasses. Not inherited. Internal use only.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
979
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
980
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
981 .. c:member:: PyObject* PyTypeObject.tp_weaklist
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
982
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
983 Weak reference list head, for weak references to this type object. Not
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
984 inherited. Internal use only.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
985
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
986 The remaining fields are only defined if the feature test macro
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
987 :const:`COUNT_ALLOCS` is defined, and are for internal use only. They are
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
988 documented here for completeness. None of these fields are inherited by
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
989 subtypes.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
990
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
991
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
992 .. c:member:: Py_ssize_t PyTypeObject.tp_allocs
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
993
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
994 Number of allocations.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
995
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
996
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
997 .. c:member:: Py_ssize_t PyTypeObject.tp_frees
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
998
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
999 Number of frees.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1000
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1001
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1002 .. c:member:: Py_ssize_t PyTypeObject.tp_maxalloc
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1003
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1004 Maximum simultaneously allocated objects.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1005
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1006
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1007 .. c:member:: PyTypeObject* PyTypeObject.tp_next
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1008
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1009 Pointer to the next type object with a non-zero :attr:`tp_allocs` field.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1010
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1011 Also, note that, in a garbage collected Python, tp_dealloc may be called from
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1012 any Python thread, not just the thread which created the object (if the object
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1013 becomes part of a refcount cycle, that cycle might be collected by a garbage
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1014 collection on any thread). This is not a problem for Python API calls, since
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1015 the thread on which tp_dealloc is called will own the Global Interpreter Lock
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1016 (GIL). However, if the object being destroyed in turn destroys objects from some
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1017 other C or C++ library, care should be taken to ensure that destroying those
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1018 objects on the thread which called tp_dealloc will not violate any assumptions
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1019 of the library.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1020
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1021
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1022 .. _number-structs:
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1023
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1024 Number Object Structures
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1025 ========================
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1026
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1027 .. sectionauthor:: Amaury Forgeot d'Arc
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1028
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1029
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1030 .. c:type:: PyNumberMethods
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1031
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1032 This structure holds pointers to the functions which an object uses to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1033 implement the number protocol. Each function is used by the function of
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1034 similar name documented in the :ref:`number` section.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1035
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1036 Here is the structure definition::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1037
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1038 typedef struct {
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1039 binaryfunc nb_add;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1040 binaryfunc nb_subtract;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1041 binaryfunc nb_multiply;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1042 binaryfunc nb_remainder;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1043 binaryfunc nb_divmod;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1044 ternaryfunc nb_power;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1045 unaryfunc nb_negative;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1046 unaryfunc nb_positive;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1047 unaryfunc nb_absolute;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1048 inquiry nb_bool;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1049 unaryfunc nb_invert;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1050 binaryfunc nb_lshift;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1051 binaryfunc nb_rshift;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1052 binaryfunc nb_and;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1053 binaryfunc nb_xor;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1054 binaryfunc nb_or;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1055 unaryfunc nb_int;
50821
df3fa40fdbed Issue #4910, patch 3/3: rename nb_long to nb_reserved
Mark Dickinson <dickinsm@gmail.com>
parents: 50812
diff changeset
1056 void *nb_reserved;
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1057 unaryfunc nb_float;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1058
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1059 binaryfunc nb_inplace_add;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1060 binaryfunc nb_inplace_subtract;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1061 binaryfunc nb_inplace_multiply;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1062 binaryfunc nb_inplace_remainder;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1063 ternaryfunc nb_inplace_power;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1064 binaryfunc nb_inplace_lshift;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1065 binaryfunc nb_inplace_rshift;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1066 binaryfunc nb_inplace_and;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1067 binaryfunc nb_inplace_xor;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1068 binaryfunc nb_inplace_or;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1069
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1070 binaryfunc nb_floor_divide;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1071 binaryfunc nb_true_divide;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1072 binaryfunc nb_inplace_floor_divide;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1073 binaryfunc nb_inplace_true_divide;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1074
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1075 unaryfunc nb_index;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1076 } PyNumberMethods;
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1077
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1078 .. note::
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1079
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1080 Binary and ternary functions must check the type of all their operands,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1081 and implement the necessary conversions (at least one of the operands is
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1082 an instance of the defined type). If the operation is not defined for the
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1083 given operands, binary and ternary functions must return
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1084 ``Py_NotImplemented``, if another error occurred they must return ``NULL``
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1085 and set an exception.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1086
50821
df3fa40fdbed Issue #4910, patch 3/3: rename nb_long to nb_reserved
Mark Dickinson <dickinsm@gmail.com>
parents: 50812
diff changeset
1087 .. note::
df3fa40fdbed Issue #4910, patch 3/3: rename nb_long to nb_reserved
Mark Dickinson <dickinsm@gmail.com>
parents: 50812
diff changeset
1088
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1089 The :c:data:`nb_reserved` field should always be ``NULL``. It
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1090 was previously called :c:data:`nb_long`, and was renamed in
50821
df3fa40fdbed Issue #4910, patch 3/3: rename nb_long to nb_reserved
Mark Dickinson <dickinsm@gmail.com>
parents: 50812
diff changeset
1091 Python 3.0.1.
df3fa40fdbed Issue #4910, patch 3/3: rename nb_long to nb_reserved
Mark Dickinson <dickinsm@gmail.com>
parents: 50812
diff changeset
1092
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1093
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1094 .. _mapping-structs:
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1095
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1096 Mapping Object Structures
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1097 =========================
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1098
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1099 .. sectionauthor:: Amaury Forgeot d'Arc
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1100
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1101
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1102 .. c:type:: PyMappingMethods
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1103
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1104 This structure holds pointers to the functions which an object uses to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1105 implement the mapping protocol. It has three members:
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1106
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1107 .. c:member:: lenfunc PyMappingMethods.mp_length
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1108
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1109 This function is used by :c:func:`PyMapping_Length` and
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1110 :c:func:`PyObject_Size`, and has the same signature. This slot may be set to
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1111 *NULL* if the object has no defined length.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1112
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1113 .. c:member:: binaryfunc PyMappingMethods.mp_subscript
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1114
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1115 This function is used by :c:func:`PyObject_GetItem` and has the same
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1116 signature. This slot must be filled for the :c:func:`PyMapping_Check`
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1117 function to return ``1``, it can be *NULL* otherwise.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1118
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1119 .. c:member:: objobjargproc PyMappingMethods.mp_ass_subscript
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1120
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1121 This function is used by :c:func:`PyObject_SetItem` and has the same
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1122 signature. If this slot is *NULL*, the object does not support item
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1123 assignment.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1124
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1125
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1126 .. _sequence-structs:
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1127
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1128 Sequence Object Structures
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1129 ==========================
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1130
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1131 .. sectionauthor:: Amaury Forgeot d'Arc
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1132
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1133
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1134 .. c:type:: PySequenceMethods
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1135
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1136 This structure holds pointers to the functions which an object uses to
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1137 implement the sequence protocol.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1138
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1139 .. c:member:: lenfunc PySequenceMethods.sq_length
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1140
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1141 This function is used by :c:func:`PySequence_Size` and :c:func:`PyObject_Size`,
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1142 and has the same signature.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1143
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1144 .. c:member:: binaryfunc PySequenceMethods.sq_concat
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1145
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1146 This function is used by :c:func:`PySequence_Concat` and has the same
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1147 signature. It is also used by the ``+`` operator, after trying the numeric
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1148 addition via the :attr:`tp_as_number.nb_add` slot.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1149
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1150 .. c:member:: ssizeargfunc PySequenceMethods.sq_repeat
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1151
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1152 This function is used by :c:func:`PySequence_Repeat` and has the same
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1153 signature. It is also used by the ``*`` operator, after trying numeric
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1154 multiplication via the :attr:`tp_as_number.nb_mul` slot.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1155
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1156 .. c:member:: ssizeargfunc PySequenceMethods.sq_item
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1157
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1158 This function is used by :c:func:`PySequence_GetItem` and has the same
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1159 signature. This slot must be filled for the :c:func:`PySequence_Check`
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1160 function to return ``1``, it can be *NULL* otherwise.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1161
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1162 Negative indexes are handled as follows: if the :attr:`sq_length` slot is
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1163 filled, it is called and the sequence length is used to compute a positive
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1164 index which is passed to :attr:`sq_item`. If :attr:`sq_length` is *NULL*,
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1165 the index is passed as is to the function.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1166
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1167 .. c:member:: ssizeobjargproc PySequenceMethods.sq_ass_item
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1168
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1169 This function is used by :c:func:`PySequence_SetItem` and has the same
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1170 signature. This slot may be left to *NULL* if the object does not support
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1171 item assignment.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1172
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1173 .. c:member:: objobjproc PySequenceMethods.sq_contains
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1174
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1175 This function may be used by :c:func:`PySequence_Contains` and has the same
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1176 signature. This slot may be left to *NULL*, in this case
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1177 :c:func:`PySequence_Contains` simply traverses the sequence until it finds a
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1178 match.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1179
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1180 .. c:member:: binaryfunc PySequenceMethods.sq_inplace_concat
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1181
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1182 This function is used by :c:func:`PySequence_InPlaceConcat` and has the same
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1183 signature. It should modify its first operand, and return it.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1184
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1185 .. c:member:: ssizeargfunc PySequenceMethods.sq_inplace_repeat
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1186
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1187 This function is used by :c:func:`PySequence_InPlaceRepeat` and has the same
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1188 signature. It should modify its first operand, and return it.
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1189
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1190 .. XXX need to explain precedence between mapping and sequence
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1191 .. XXX explains when to implement the sq_inplace_* slots
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1192
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1193
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1194 .. _buffer-structs:
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1195
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1196 Buffer Object Structures
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1197 ========================
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1198
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1199 .. sectionauthor:: Greg J. Stein <greg@lyra.org>
49205
3302045bae97 add documentation for the new buffer interface based on PEP 3118; I hope it's at least 60% right...
Benjamin Peterson <benjamin@python.org>
parents: 48741
diff changeset
1200 .. sectionauthor:: Benjamin Peterson
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1201 .. sectionauthor:: Stefan Krah
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1202
65137
521eac31a893 Migrate to Sphinx 1.0 C language constructs.
Georg Brandl <georg@python.org>
parents: 59617
diff changeset
1203 .. c:type:: PyBufferProcs
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1204
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1205 This structure holds pointers to the functions required by the
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1206 :ref:`Buffer protocol <bufferobjects>`. The protocol defines how
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1207 an exporter object can expose its internal data to consumer objects.
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1208
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1209 .. c:member:: getbufferproc PyBufferProcs.bf_getbuffer
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1210
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1211 The signature of this function is::
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1212
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1213 int (PyObject *exporter, Py_buffer *view, int flags);
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1214
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1215 Handle a request to *exporter* to fill in *view* as specified by *flags*.
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1216 Except for point (3), an implementation of this function MUST take these
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1217 steps:
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1218
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1219 (1) Check if the request can be met. If not, raise :c:data:`PyExc_BufferError`,
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1220 set :c:data:`view->obj` to *NULL* and return -1.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1221
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1222 (2) Fill in the requested fields.
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1223
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1224 (3) Increment an internal counter for the number of exports.
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1225
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1226 (4) Set :c:data:`view->obj` to *exporter* and increment :c:data:`view->obj`.
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1227
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1228 (5) Return 0.
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1229
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1230 If *exporter* is part of a chain or tree of buffer providers, two main
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1231 schemes can be used:
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1232
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1233 * Re-export: Each member of the tree acts as the exporting object and
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1234 sets :c:data:`view->obj` to a new reference to itself.
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1235
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1236 * Redirect: The buffer request is redirected to the root object of the
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1237 tree. Here, :c:data:`view->obj` will be a new reference to the root
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1238 object.
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1239
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1240 The individual fields of *view* are described in section
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1241 :ref:`Buffer structure <buffer-structure>`, the rules how an exporter
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1242 must react to specific requests are in section
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1243 :ref:`Buffer request types <buffer-request-types>`.
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1244
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1245 All memory pointed to in the :c:type:`Py_buffer` structure belongs to
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1246 the exporter and must remain valid until there are no consumers left.
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1247 :c:member:`~Py_buffer.format`, :c:member:`~Py_buffer.shape`,
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1248 :c:member:`~Py_buffer.strides`, :c:member:`~Py_buffer.suboffsets`
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1249 and :c:member:`~Py_buffer.internal`
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1250 are read-only for the consumer.
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1251
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1252 :c:func:`PyBuffer_FillInfo` provides an easy way of exposing a simple
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1253 bytes buffer while dealing correctly with all request types.
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1255 :c:func:`PyObject_GetBuffer` is the interface for the consumer that
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1256 wraps this function.
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1257
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1258 .. c:member:: releasebufferproc PyBufferProcs.bf_releasebuffer
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1259
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1260 The signature of this function is::
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1261
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1262 void (PyObject *exporter, Py_buffer *view);
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1263
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1264 Handle a request to release the resources of the buffer. If no resources
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1265 need to be released, :c:member:`PyBufferProcs.bf_releasebuffer` may be
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1266 *NULL*. Otherwise, a standard implementation of this function will take
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1267 these optional steps:
75254
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1268
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
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parents: 75254
diff changeset
1269 (1) Decrement an internal counter for the number of exports.
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Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1270
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da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
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parents: 75254
diff changeset
1271 (2) If the counter is 0, free all memory associated with *view*.
75254
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Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1272
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Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1273 The exporter MUST use the :c:member:`~Py_buffer.internal` field to keep
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
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parents: 75254
diff changeset
1274 track of buffer-specific resources. This field is guaranteed to remain
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1275 constant, while a consumer MAY pass a copy of the original buffer as the
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1276 *view* argument.
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1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1277
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1278
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Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1279 This function MUST NOT decrement :c:data:`view->obj`, since that is
75455
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1280 done automatically in :c:func:`PyBuffer_Release` (this scheme is
da2aaced21bd Issue #14181: Improve clarity in the documentation for the multi-purpose
Stefan Krah <skrah@bytereef.org>
parents: 75254
diff changeset
1281 useful for breaking reference cycles).
44812
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1282
1e8b9e7c34ce Split C API docs in Py3k branch.
Georg Brandl <georg@python.org>
parents:
diff changeset
1283
75254
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Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1284 :c:func:`PyBuffer_Release` is the interface for the consumer that
3f9b3b6f7ff0 - Issue #10181: New memoryview implementation fixes multiple ownership
Stefan Krah <skrah@bytereef.org>
parents: 71791
diff changeset
1285 wraps this function.