cpython-lru_cache-weakref: Doc/lib/libthreading.tex annotate

annotate Doc/lib/libthreading.tex @ 17322:bd110eadc19a legacy-trunk

One-liner critical fix from Jim Fulton: Eric's string-method crusade got the order backwards in a line (for .find()).

author	Tim Peters <tim.peters@gmail.com>
date	Thu, 05 Apr 2001 22:26:23 +0000
parents	c5f449aa4345
children	50e3380b086a

rev	line source
8918 acfffe14628e New section header style. Fred Drake <fdrake@acm.org> parents: 8767 diff changeset	1 \section{\module{threading} ---
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	2 Higher-level threading interface}
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	3
8716 760dcf197048 Adjusted to use the new module synopsis support macros. Fred Drake <fdrake@acm.org> parents: 8683 diff changeset	4 \declaremodule{standard}{threading}
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	5 \modulesynopsis{Higher-level threading interface.}
8716 760dcf197048 Adjusted to use the new module synopsis support macros. Fred Drake <fdrake@acm.org> parents: 8683 diff changeset	6
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	7
8767 8434e9d00b5a Fix the synopsis. Fred Drake <fdrake@acm.org> parents: 8716 diff changeset	8 This module constructs higher-level threading interfaces on top of the
10703 e4e800a78d8d Make internal module references hyperlinks wherever it makes sense. Fred Drake <fdrake@acm.org> parents: 10392 diff changeset	9 lower level \refmodule{thread} module.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	10
8767 8434e9d00b5a Fix the synopsis. Fred Drake <fdrake@acm.org> parents: 8716 diff changeset	11 This module is safe for use with \samp{from threading import *}. It
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	12 defines the following functions and objects:
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	13
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	14 \begin{funcdesc}{activeCount}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	15 Return the number of currently active \class{Thread} objects.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	16 The returned count is equal to the length of the list returned by
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	17 \function{enumerate()}.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	18 A function that returns the number of currently active threads.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	19 \end{funcdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	20
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	21 \begin{funcdesc}{Condition}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	22 A factory function that returns a new condition variable object.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	23 A condition variable allows one or more threads to wait until they
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	24 are notified by another thread.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	25 \end{funcdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	26
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	27 \begin{funcdesc}{currentThread}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	28 Return the current \class{Thread} object, corresponding to the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	29 caller's thread of control. If the caller's thread of control was not
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	30 created through the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	31 \module{threading} module, a dummy thread object with limited functionality
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	32 is returned.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	33 \end{funcdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	34
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	35 \begin{funcdesc}{enumerate}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	36 Return a list of all currently active \class{Thread} objects.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	37 The list includes daemonic threads, dummy thread objects created
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	38 by \function{currentThread()}, and the main thread. It excludes terminated
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	39 threads and threads that have not yet been started.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	40 \end{funcdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	41
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	42 \begin{funcdesc}{Event}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	43 A factory function that returns a new event object. An event
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	44 manages a flag that can be set to true with the \method{set()} method and
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	45 reset to false with the \method{clear()} method. The \method{wait()} method blocks
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	46 until the flag is true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	47 \end{funcdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	48
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	49 \begin{funcdesc}{Lock}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	50 A factory function that returns a new primitive lock object. Once
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	51 a thread has acquired it, subsequent attempts to acquire it block,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	52 until it is released; any thread may release it.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	53 \end{funcdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	54
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	55 \begin{funcdesc}{RLock}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	56 A factory function that returns a new reentrant lock object.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	57 A reentrant lock must be released by the thread that acquired it.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	58 Once a thread has acquired a reentrant lock, the same thread may
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	59 acquire it again without blocking; the thread must release it once
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	60 for each time it has acquired it.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	61 \end{funcdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	62
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	63 \begin{funcdesc}{Semaphore}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	64 A factory function that returns a new semaphore object. A
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	65 semaphore manages a counter representing the number of \method{release()}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	66 calls minus the number of \method{acquire()} calls, plus an initial value.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	67 The \method{acquire()} method blocks if necessary until it can return
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	68 without making the counter negative.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	69 \end{funcdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	70
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	71 \begin{classdesc}{Thread}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	72 A class that represents a thread of control. This class can be safely subclassed in a limited fashion.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	73 \end{classdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	74
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	75 Detailed interfaces for the objects are documented below.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	76
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	77 The design of this module is loosely based on Java's threading model.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	78 However, where Java makes locks and condition variables basic behavior
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	79 of every object, they are separate objects in Python. Python's \class{Thread}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	80 class supports a subset of the behavior of Java's Thread class;
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	81 currently, there are no priorities, no thread groups, and threads
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	82 cannot be destroyed, stopped, suspended, resumed, or interrupted. The
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	83 static methods of Java's Thread class, when implemented, are mapped to
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	84 module-level functions.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	85
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	86 All of the methods described below are executed atomically.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	87
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	88
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	89 \subsection{Lock Objects \label{lock-objects}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	90
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	91 A primitive lock is a synchronization primitive that is not owned
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	92 by a particular thread when locked. In Python, it is currently
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	93 the lowest level synchronization primitive available, implemented
10703 e4e800a78d8d Make internal module references hyperlinks wherever it makes sense. Fred Drake <fdrake@acm.org> parents: 10392 diff changeset	94 directly by the \refmodule{thread} extension module.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	95
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	96 A primitive lock is in one of two states, ``locked'' or ``unlocked''.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	97 It is created in the unlocked state. It has two basic methods,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	98 \method{acquire()} and \method{release()}. When the state is
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	99 unlocked, \method{acquire()} changes the state to locked and returns
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	100 immediately. When the state is locked, \method{acquire()} blocks
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	101 until a call to \method{release()} in another thread changes it to
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	102 unlocked, then the \method{acquire()} call resets it to locked and
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	103 returns. The \method{release()} method should only be called in the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	104 locked state; it changes the state to unlocked and returns
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	105 immediately. When more than one thread is blocked in
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	106 \method{acquire()} waiting for the state to turn to unlocked, only one
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	107 thread proceeds when a \method{release()} call resets the state to
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	108 unlocked; which one of the waiting threads proceeds is not defined,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	109 and may vary across implementations.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	110
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	111 All methods are executed atomically.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	112
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	113 \begin{methoddesc}{acquire}{\optional{blocking\code{ = 1}}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	114 Acquire a lock, blocking or non-blocking.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	115
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	116 When invoked without arguments, block until the lock is
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	117 unlocked, then set it to locked, and return. There is no
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	118 return value in this case.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	119
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	120 When invoked with the \var{blocking} argument set to true, do the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	121 same thing as when called without arguments, and return true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	122
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	123 When invoked with the \var{blocking} argument set to false, do not
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	124 block. If a call without an argument would block, return false
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	125 immediately; otherwise, do the same thing as when called
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	126 without arguments, and return true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	127 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	128
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	129 \begin{methoddesc}{release}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	130 Release a lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	131
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	132 When the lock is locked, reset it to unlocked, and return. If
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	133 any other threads are blocked waiting for the lock to become
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	134 unlocked, allow exactly one of them to proceed.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	135
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	136 Do not call this method when the lock is unlocked.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	137
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	138 There is no return value.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	139 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	140
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	141
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	142 \subsection{RLock Objects \label{rlock-objects}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	143
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	144 A reentrant lock is a synchronization primitive that may be
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	145 acquired multiple times by the same thread. Internally, it uses
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	146 the concepts of ``owning thread'' and ``recursion level'' in
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	147 addition to the locked/unlocked state used by primitive locks. In
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	148 the locked state, some thread owns the lock; in the unlocked
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	149 state, no thread owns it.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	150
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	151 To lock the lock, a thread calls its \method{acquire()} method; this
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	152 returns once the thread owns the lock. To unlock the lock, a
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	153 thread calls its \method{release()} method. \method{acquire()}/\method{release()} call pairs
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	154 may be nested; only the final \method{release()} (i.e. the \method{release()} of the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	155 outermost pair) resets the lock to unlocked and allows another
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	156 thread blocked in \method{acquire()} to proceed.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	157
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	158 \begin{methoddesc}{acquire}{\optional{blocking\code{ = 1}}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	159 Acquire a lock, blocking or non-blocking.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	160
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	161 When invoked without arguments: if this thread already owns
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	162 the lock, increment the recursion level by one, and return
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	163 immediately. Otherwise, if another thread owns the lock,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	164 block until the lock is unlocked. Once the lock is unlocked
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	165 (not owned by any thread), then grab ownership, set the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	166 recursion level to one, and return. If more than one thread
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	167 is blocked waiting until the lock is unlocked, only one at a
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	168 time will be able to grab ownership of the lock. There is no
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	169 return value in this case.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	170
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	171 When invoked with the \var{blocking} argument set to true, do the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	172 same thing as when called without arguments, and return true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	173
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	174 When invoked with the \var{blocking} argument set to false, do not
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	175 block. If a call without an argument would block, return false
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	176 immediately; otherwise, do the same thing as when called
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	177 without arguments, and return true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	178 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	179
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	180 \begin{methoddesc}{release}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	181 Release a lock, decrementing the recursion level. If after the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	182 decrement it is zero, reset the lock to unlocked (not owned by any
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	183 thread), and if any other threads are blocked waiting for the lock to
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	184 become unlocked, allow exactly one of them to proceed. If after the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	185 decrement the recursion level is still nonzero, the lock remains
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	186 locked and owned by the calling thread.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	187
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	188 Only call this method when the calling thread owns the lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	189 Do not call this method when the lock is unlocked.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	190
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	191 There is no return value.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	192 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	193
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	194
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	195 \subsection{Condition Objects \label{condition-objects}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	196
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	197 A condition variable is always associated with some kind of lock;
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	198 this can be passed in or one will be created by default. (Passing
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	199 one in is useful when several condition variables must share the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	200 same lock.)
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	201
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	202 A condition variable has \method{acquire()} and \method{release()}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	203 methods that call the corresponding methods of the associated lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	204 It also has a \method{wait()} method, and \method{notify()} and
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	205 \method{notifyAll()} methods. These three must only be called when
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	206 the calling thread has acquired the lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	207
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	208 The \method{wait()} method releases the lock, and then blocks until it
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	209 is awakened by a \method{notify()} or \method{notifyAll()} call for
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	210 the same condition variable in another thread. Once awakened, it
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	211 re-acquires the lock and returns. It is also possible to specify a
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	212 timeout.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	213
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	214 The \method{notify()} method wakes up one of the threads waiting for
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	215 the condition variable, if any are waiting. The \method{notifyAll()}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	216 method wakes up all threads waiting for the condition variable.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	217
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	218 Note: the \method{notify()} and \method{notifyAll()} methods don't
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	219 release the lock; this means that the thread or threads awakened will
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	220 not return from their \method{wait()} call immediately, but only when
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	221 the thread that called \method{notify()} or \method{notifyAll()}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	222 finally relinquishes ownership of the lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	223
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	224 Tip: the typical programming style using condition variables uses the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	225 lock to synchronize access to some shared state; threads that are
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	226 interested in a particular change of state call \method{wait()}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	227 repeatedly until they see the desired state, while threads that modify
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	228 the state call \method{notify()} or \method{notifyAll()} when they
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	229 change the state in such a way that it could possibly be a desired
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	230 state for one of the waiters. For example, the following code is a
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	231 generic producer-consumer situation with unlimited buffer capacity:
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	232
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	233 \begin{verbatim}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	234 # Consume one item
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	235 cv.acquire()
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	236 while not an_item_is_available():
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	237 cv.wait()
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	238 get_an_available_item()
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	239 cv.release()
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	240
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	241 # Produce one item
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	242 cv.acquire()
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	243 make_an_item_available()
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	244 cv.notify()
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	245 cv.release()
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	246 \end{verbatim}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	247
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	248 To choose between \method{notify()} and \method{notifyAll()}, consider
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	249 whether one state change can be interesting for only one or several
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	250 waiting threads. E.g. in a typical producer-consumer situation,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	251 adding one item to the buffer only needs to wake up one consumer
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	252 thread.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	253
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	254 \begin{classdesc}{Condition}{\optional{lock}}
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	255 If the \var{lock} argument is given and not \code{None}, it must be a
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	256 \class{Lock} or \class{RLock} object, and it is used as the underlying
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	257 lock. Otherwise, a new \class{RLock} object is created and used as
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	258 the underlying lock.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	259 \end{classdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	260
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	261 \begin{methoddesc}{acquire}{*args}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	262 Acquire the underlying lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	263 This method calls the corresponding method on the underlying
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	264 lock; the return value is whatever that method returns.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	265 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	266
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	267 \begin{methoddesc}{release}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	268 Release the underlying lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	269 This method calls the corresponding method on the underlying
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	270 lock; there is no return value.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	271 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	272
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	273 \begin{methoddesc}{wait}{\optional{timeout}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	274 Wait until notified or until a timeout occurs.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	275 This must only be called when the calling thread has acquired the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	276 lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	277
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	278 This method releases the underlying lock, and then blocks until it is
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	279 awakened by a \method{notify()} or \method{notifyAll()} call for the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	280 same condition variable in another thread, or until the optional
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	281 timeout occurs. Once awakened or timed out, it re-acquires the lock
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	282 and returns.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	283
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	284 When the \var{timeout} argument is present and not \code{None}, it
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	285 should be a floating point number specifying a timeout for the
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	286 operation in seconds (or fractions thereof).
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	287
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	288 When the underlying lock is an \class{RLock}, it is not released using
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	289 its \method{release()} method, since this may not actually unlock the
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	290 lock when it was acquired multiple times recursively. Instead, an
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	291 internal interface of the \class{RLock} class is used, which really
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	292 unlocks it even when it has been recursively acquired several times.
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	293 Another internal interface is then used to restore the recursion level
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	294 when the lock is reacquired.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	295 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	296
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	297 \begin{methoddesc}{notify}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	298 Wake up a thread waiting on this condition, if any.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	299 This must only be called when the calling thread has acquired the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	300 lock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	301
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	302 This method wakes up one of the threads waiting for the condition
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	303 variable, if any are waiting; it is a no-op if no threads are waiting.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	304
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	305 The current implementation wakes up exactly one thread, if any are
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	306 waiting. However, it's not safe to rely on this behavior. A future,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	307 optimized implementation may occasionally wake up more than one
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	308 thread.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	309
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	310 Note: the awakened thread does not actually return from its
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	311 \method{wait()} call until it can reacquire the lock. Since
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	312 \method{notify()} does not release the lock, its caller should.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	313 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	314
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	315 \begin{methoddesc}{notifyAll}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	316 Wake up all threads waiting on this condition. This method acts like
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	317 \method{notify()}, but wakes up all waiting threads instead of one.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	318 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	319
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	320
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	321 \subsection{Semaphore Objects \label{semaphore-objects}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	322
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	323 This is one of the oldest synchronization primitives in the history of
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	324 computer science, invented by the early Dutch computer scientist
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	325 Edsger W. Dijkstra (he used \method{P()} and \method{V()} instead of
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	326 \method{acquire()} and \method{release()}).
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	327
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	328 A semaphore manages an internal counter which is decremented by each
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	329 \method{acquire()} call and incremented by each \method{release()}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	330 call. The counter can never go below zero; when \method{acquire()}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	331 finds that it is zero, it blocks, waiting until some other thread
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	332 calls \method{release()}.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	333
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	334 \begin{classdesc}{Semaphore}{\optional{value}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	335 The optional argument gives the initial value for the internal
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	336 counter; it defaults to \code{1}.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	337 \end{classdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	338
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	339 \begin{methoddesc}{acquire}{\optional{blocking}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	340 Acquire a semaphore.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	341
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	342 When invoked without arguments: if the internal counter is larger than
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	343 zero on entry, decrement it by one and return immediately. If it is
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	344 zero on entry, block, waiting until some other thread has called
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	345 \method{release()} to make it larger than zero. This is done with
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	346 proper interlocking so that if multiple \method{acquire()} calls are
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	347 blocked, \method{release()} will wake exactly one of them up. The
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	348 implementation may pick one at random, so the order in which blocked
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	349 threads are awakened should not be relied on. There is no return
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	350 value in this case.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	351
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	352 When invoked with \var{blocking} set to true, do the same thing as
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	353 when called without arguments, and return true.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	354
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	355 When invoked with \var{blocking} set to false, do not block. If a
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	356 call without an argument would block, return false immediately;
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	357 otherwise, do the same thing as when called without arguments, and
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	358 return true.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	359 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	360
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	361 \begin{methoddesc}{release}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	362 Release a semaphore,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	363 incrementing the internal counter by one. When it was zero on
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	364 entry and another thread is waiting for it to become larger
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	365 than zero again, wake up that thread.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	366 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	367
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	368
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	369 \subsection{Event Objects \label{event-objects}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	370
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	371 This is one of the simplest mechanisms for communication between
10730 c5f449aa4345 Fix a grammatical error reported by Detlef Lannert Fred Drake <fdrake@acm.org> parents: 10703 diff changeset	372 threads: one thread signals an event and one or more other threads
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	373 are waiting for it.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	374
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	375 An event object manages an internal flag that can be set to true with
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	376 the \method{set()} method and reset to false with the \method{clear()} method. The
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	377 \method{wait()} method blocks until the flag is true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	378
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	379
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	380 \begin{classdesc}{Event}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	381 The internal flag is initially false.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	382 \end{classdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	383
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	384 \begin{methoddesc}{isSet}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	385 Return true if and only if the internal flag is true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	386 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	387
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	388 \begin{methoddesc}{set}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	389 Set the internal flag to true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	390 All threads waiting for it to become true are awakened.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	391 Threads that call \method{wait()} once the flag is true will not block
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	392 at all.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	393 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	394
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	395 \begin{methoddesc}{clear}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	396 Reset the internal flag to false.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	397 Subsequently, threads calling \method{wait()} will block until \method{set()} is
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	398 called to set the internal flag to true again.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	399 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	400
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	401 \begin{methoddesc}{wait}{\optional{timeout}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	402 Block until the internal flag is true.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	403 If the internal flag is true on entry, return immediately. Otherwise,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	404 block until another thread calls \method{set()} to set the flag to
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	405 true, or until the optional timeout occurs.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	406
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	407 When the timeout argument is present and not \code{None}, it should be a
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	408 floating point number specifying a timeout for the operation in
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	409 seconds (or fractions thereof).
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	410 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	411
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	412
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	413 \subsection{Thread Objects \label{thread-objects}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	414
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	415 This class represents an activity that is run in a separate thread
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	416 of control. There are two ways to specify the activity: by
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	417 passing a callable object to the constructor, or by overriding the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	418 \method{run()} method in a subclass. No other methods (except for the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	419 constructor) should be overridden in a subclass. In other words,
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	420 \emph{only} override the \method{__init__()} and \method{run()}
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	421 methods of this class.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	422
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	423 Once a thread object is created, its activity must be started by
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	424 calling the thread's \method{start()} method. This invokes the
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	425 \method{run()} method in a separate thread of control.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	426
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	427 Once the thread's activity is started, the thread is considered
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	428 'alive' and 'active' (these concepts are almost, but not quite
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	429 exactly, the same; their definition is intentionally somewhat
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	430 vague). It stops being alive and active when its \method{run()}
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	431 method terminates -- either normally, or by raising an unhandled
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	432 exception. The \method{isAlive()} method tests whether the thread is
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	433 alive.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	434
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	435 Other threads can call a thread's \method{join()} method. This blocks
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	436 the calling thread until the thread whose \method{join()} method is
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	437 called is terminated.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	438
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	439 A thread has a name. The name can be passed to the constructor,
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	440 set with the \method{setName()} method, and retrieved with the
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	441 \method{getName()} method.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	442
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	443 A thread can be flagged as a ``daemon thread''. The significance
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	444 of this flag is that the entire Python program exits when only
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	445 daemon threads are left. The initial value is inherited from the
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	446 creating thread. The flag can be set with the \method{setDaemon()}
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	447 method and retrieved with the \method{getDaemon()} method.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	448
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	449 There is a ``main thread'' object; this corresponds to the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	450 initial thread of control in the Python program. It is not a
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	451 daemon thread.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	452
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	453 There is the possibility that ``dummy thread objects'' are
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	454 created. These are thread objects corresponding to ``alien
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	455 threads''. These are threads of control started outside the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	456 threading module, e.g. directly from C code. Dummy thread objects
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	457 have limited functionality; they are always considered alive,
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	458 active, and daemonic, and cannot be \method{join()}ed. They are never
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	459 deleted, since it is impossible to detect the termination of alien
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	460 threads.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	461
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	462
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	463 \begin{classdesc}{Thread}{group=None, target=None, name=None,
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	464 args=(), kwargs=\{\}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	465 This constructor should always be called with keyword
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	466 arguments. Arguments are:
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	467
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	468 \var{group}
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	469 Should be \code{None}; reserved for future extension when a
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	470 \class{ThreadGroup} class is implemented.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	471
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	472 \var{target}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	473 Callable object to be invoked by the \method{run()} method.
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	474 Defaults to \code{None}, meaning nothing is called.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	475
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	476 \var{name}
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	477 The thread name. By default, a unique name is constructed of the form
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	478 ``Thread-\var{N}'' where \var{N} is a small decimal number.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	479
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	480 \var{args}
f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	481 Argument tuple for the target invocation. Defaults to \code{()}.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	482
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	483 \var{kwargs}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	484 Keyword argument dictionary for the target invocation.
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	485 Defaults to \code{\{\}}.
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	486
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	487 If the subclass overrides the constructor, it must make sure
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	488 to invoke the base class constructor (\code{Thread.__init__()})
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	489 before doing anything else to the thread.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	490 \end{classdesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	491
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	492
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	493
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	494 \begin{methoddesc}{start}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	495 Start the thread's activity.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	496
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	497 This must be called at most once per thread object. It
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	498 arranges for the object's \method{run()} method to be invoked in a
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	499 separate thread of control.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	500 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	501
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	502
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	503
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	504 \begin{methoddesc}{run}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	505 Method representing the thread's activity.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	506
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	507 You may override this method in a subclass. The standard
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	508 \method{run()} method invokes the callable object passed to the object's constructor as the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	509 \var{target} argument, if any, with sequential and keyword
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	510 arguments taken from the \var{args} and \var{kwargs} arguments,
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	511 respectively.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	512 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	513
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	514
10392 f54bac5af98c Fixed tons of small markup problems. Fred Drake <fdrake@acm.org> parents: 8918 diff changeset	515 \begin{methoddesc}{join}{\optional{timeout}}
8683 a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	516 Wait until the thread terminates.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	517 This blocks the calling thread until the thread whose \method{join()}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	518 method is called terminates -- either normally or through an
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	519 unhandled exception -- or until the optional timeout occurs.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	520
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	521 When the \var{timeout} argument is present and not \code{None}, it should
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	522 be a floating point number specifying a timeout for the
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	523 operation in seconds (or fractions thereof).
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	524
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	525 A thread can be \method{join()}ed many times.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	526
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	527 A thread cannot join itself because this would cause a
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	528 deadlock.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	529
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	530 It is an error to attempt to \method{join()} a thread before it has
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	531 been started.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	532 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	533
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	534
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	535
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	536 \begin{methoddesc}{getName}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	537 Return the thread's name.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	538 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	539
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	540 \begin{methoddesc}{setName}{name}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	541 Set the thread's name.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	542
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	543 The name is a string used for identification purposes only.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	544 It has no semantics. Multiple threads may be given the same
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	545 name. The initial name is set by the constructor.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	546 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	547
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	548 \begin{methoddesc}{isAlive}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	549 Return whether the thread is alive.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	550
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	551 Roughly, a thread is alive from the moment the \method{start()} method
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	552 returns until its \method{run()} method terminates.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	553 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	554
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	555 \begin{methoddesc}{isDaemon}{}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	556 Return the thread's daemon flag.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	557 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	558
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	559 \begin{methoddesc}{setDaemon}{daemonic}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	560 Set the thread's daemon flag to the Boolean value \var{daemonic}.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	561 This must be called before \method{start()} is called.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	562
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	563 The initial value is inherited from the creating thread.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	564
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	565 The entire Python program exits when no active non-daemon
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	566 threads are left.
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	567 \end{methoddesc}
a0324a3068e9 Added libthreading.tex ; this is mostly the contents of threading_api.py, Andrew M. Kuchling <amk@amk.ca> parents: diff changeset	568

Mercurial > cpython-lru_cache-weakref

annotate Doc/lib/libthreading.tex @ 17322:bd110eadc19a legacy-trunk