Mercurial > cpython-lru_cache-weakref
annotate Python/errors.c @ 1912:ada19aaaf8c0 legacy-trunk
* Python/errors.c (err_clear): clear interpreter stack trace
| author | Guido van Rossum <guido@python.org> |
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| date | Thu, 29 Sep 1994 09:39:39 +0000 |
| parents | 79e420805c67 |
| children | a70883803338 |
| rev | line source |
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| 145 | 1 /*********************************************************** |
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2 Copyright 1991, 1992, 1993, 1994 by Stichting Mathematisch Centrum, |
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3 Amsterdam, The Netherlands. |
| 145 | 4 |
| 5 All Rights Reserved | |
| 6 | |
| 7 Permission to use, copy, modify, and distribute this software and its | |
| 8 documentation for any purpose and without fee is hereby granted, | |
| 9 provided that the above copyright notice appear in all copies and that | |
| 10 both that copyright notice and this permission notice appear in | |
| 11 supporting documentation, and that the names of Stichting Mathematisch | |
| 12 Centrum or CWI not be used in advertising or publicity pertaining to | |
| 13 distribution of the software without specific, written prior permission. | |
| 14 | |
| 15 STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO | |
| 16 THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND | |
| 17 FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE | |
| 18 FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
| 19 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
| 20 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT | |
| 21 OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
| 22 | |
| 23 ******************************************************************/ | |
| 24 | |
| 6 | 25 /* Error handling -- see also run.c */ |
| 26 | |
| 27 /* New error handling interface. | |
| 28 | |
| 29 The following problem exists (existed): methods of built-in modules | |
| 30 are called with 'self' and 'args' arguments, but without a context | |
| 31 argument, so they have no way to raise a specific exception. | |
| 32 The same is true for the object implementations: no context argument. | |
| 33 The old convention was to set 'errno' and to return NULL. | |
| 34 The caller (usually call_function() in eval.c) detects the NULL | |
| 35 return value and then calls puterrno(ctx) to turn the errno value | |
| 36 into a true exception. Problems with this approach are: | |
| 37 - it used standard errno values to indicate Python-specific errors, | |
| 86 | 38 but this means that when such an error code is reported by a system |
| 39 call (e.g., in module posix), the user gets a confusing message | |
| 6 | 40 - errno is a global variable, which makes extensions to a multi- |
| 41 threading environment difficult; e.g., in IRIX, multi-threaded | |
| 86 | 42 programs must use the function oserror() instead of looking in errno |
| 6 | 43 - there is no portable way to add new error numbers for specic |
| 44 situations -- the value space for errno is reserved to the OS, yet | |
| 45 the way to turn module-specific errors into a module-specific | |
| 46 exception requires module-specific values for errno | |
| 47 - there is no way to add a more situation-specific message to an | |
| 48 error. | |
| 49 | |
| 50 The new interface solves all these problems. To return an error, a | |
| 86 | 51 built-in function calls err_set(exception), err_setval(exception, |
| 6 | 52 value) or err_setstr(exception, string), and returns NULL. These |
| 53 functions save the value for later use by puterrno(). To adapt this | |
| 54 scheme to a multi-threaded environment, only the implementation of | |
| 55 err_setval() has to be changed. | |
| 56 */ | |
| 57 | |
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58 #include "allobjects.h" |
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59 #include "traceback.h" |
| 6 | 60 |
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61 #include <errno.h> |
| 86 | 62 |
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63 extern char *strerror PROTO((int)); |
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64 |
| 6 | 65 /* Last exception stored by err_setval() */ |
| 66 | |
| 67 static object *last_exception; | |
| 68 static object *last_exc_val; | |
| 69 | |
| 70 void | |
| 71 err_setval(exception, value) | |
| 72 object *exception; | |
| 73 object *value; | |
| 74 { | |
| 86 | 75 XDECREF(last_exception); |
| 76 XINCREF(exception); | |
| 6 | 77 last_exception = exception; |
| 78 | |
| 86 | 79 XDECREF(last_exc_val); |
| 80 XINCREF(value); | |
| 6 | 81 last_exc_val = value; |
| 82 } | |
| 83 | |
| 84 void | |
| 85 err_set(exception) | |
| 86 object *exception; | |
| 87 { | |
| 88 err_setval(exception, (object *)NULL); | |
| 89 } | |
| 90 | |
| 91 void | |
| 92 err_setstr(exception, string) | |
| 93 object *exception; | |
| 94 char *string; | |
| 95 { | |
| 96 object *value = newstringobject(string); | |
| 97 err_setval(exception, value); | |
| 86 | 98 XDECREF(value); |
| 6 | 99 } |
| 100 | |
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101 |
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102 object * |
| 6 | 103 err_occurred() |
| 104 { | |
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105 return last_exception; |
| 6 | 106 } |
| 107 | |
| 108 void | |
| 109 err_get(p_exc, p_val) | |
| 110 object **p_exc; | |
| 111 object **p_val; | |
| 112 { | |
| 113 *p_exc = last_exception; | |
| 114 last_exception = NULL; | |
| 115 *p_val = last_exc_val; | |
| 116 last_exc_val = NULL; | |
| 117 } | |
| 118 | |
| 119 void | |
| 120 err_clear() | |
| 121 { | |
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122 object *tb; |
| 86 | 123 XDECREF(last_exception); |
| 124 last_exception = NULL; | |
| 125 XDECREF(last_exc_val); | |
| 126 last_exc_val = NULL; | |
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127 /* Also clear interpreter stack trace */ |
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128 tb = tb_fetch(); |
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129 XDECREF(tb); |
| 6 | 130 } |
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131 |
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132 /* Convenience functions to set a type error exception and return 0 */ |
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133 |
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134 int |
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135 err_badarg() |
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136 { |
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137 err_setstr(TypeError, "illegal argument type for built-in operation"); |
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138 return 0; |
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139 } |
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140 |
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141 object * |
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142 err_nomem() |
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143 { |
| 86 | 144 err_set(MemoryError); |
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145 return NULL; |
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146 } |
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147 |
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148 object * |
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149 err_errno(exc) |
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150 object *exc; |
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151 { |
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152 object *v; |
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153 int i = errno; |
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154 if (i == EINTR && sigcheck()) |
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155 return NULL; |
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156 v = mkvalue("(is)", i, strerror(i)); |
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157 if (v != NULL) { |
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158 err_setval(exc, v); |
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159 DECREF(v); |
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160 } |
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161 return NULL; |
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162 } |
| 22 | 163 |
| 164 void | |
| 165 err_badcall() | |
| 166 { | |
| 167 err_setstr(SystemError, "bad argument to internal function"); | |
| 168 } |