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| author | rpj <rpj> | 2005-05-05 14:18:27 +0000 |
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| committer | rpj <rpj> | 2005-05-05 14:18:27 +0000 |
| commit | 41f88a82b33cdb357c83b582381232733ed2d039 (patch) | |
| tree | b3690e999b4d934fce7aab79b2693ab086a4ad46 /manual/pthread_mutexattr_init.html | |
| parent | b75686484d99c90317b64184ce5080093ee7d2a9 (diff) | |
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diff --git a/manual/pthread_mutexattr_init.html b/manual/pthread_mutexattr_init.html new file mode 100644 index 0000000..3ab5a09 --- /dev/null +++ b/manual/pthread_mutexattr_init.html @@ -0,0 +1,155 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<HTML> +<HEAD> + <META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=utf-8"> + <TITLE>PTHREAD_MUTEXATTR(3) manual page</TITLE> + <META NAME="GENERATOR" CONTENT="OpenOffice.org 1.1.3 (Linux)"> + <META NAME="CREATED" CONTENT="20050504;23040500"> + <META NAME="CHANGED" CONTENT="20050505;18370400"> + <!-- manual page source format generated by PolyglotMan v3.2, --> + <!-- available at http://polyglotman.sourceforge.net/ --> +</HEAD> +<BODY LANG="en-GB" BGCOLOR="#ffffff" DIR="LTR"> +<P><A HREF="#toc">Table of Contents</A></P> +<H2><A HREF="#toc0" NAME="sect0">Name</A></H2> +<P>pthread_mutexattr_init, pthread_mutexattr_destroy, +pthread_mutexattr_settype, pthread_mutexattr_gettype - mutex creation +attributes +</P> +<H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2> +<P><B>#include <pthread.h></B> +</P> +<P><B>int pthread_mutexattr_init(pthread_mutexattr_t *</B><I>attr</I><B>);</B> +</P> +<P><B>int pthread_mutexattr_destroy(pthread_mutexattr_t *</B><I>attr</I><B>);</B> +</P> +<P><B>int pthread_mutexattr_settype(pthread_mutexattr_t *</B><I>attr</I><B>, +int </B><I>type</I><B>);</B> +</P> +<P><B>int pthread_mutexattr_gettype(const pthread_mutexattr_t *</B><I>attr</I><B>, +int *</B><I>type</I><B>);</B> +</P> +<P><B>int pthread_mutexattr_setkind_np(pthread_mutexattr_t *</B><I>attr</I><B>, +int </B><I>type</I><B>);</B> +</P> +<P><B>int pthread_mutexattr_getkind_np(const pthread_mutexattr_t +*</B><I>attr</I><B>, int *</B><I>type</I><B>);</B> +</P> +<H2><A HREF="#toc2" NAME="sect2">Description</A></H2> +<P>Mutex attributes can be specified at mutex creation time, by +passing a mutex attribute object as second argument to +<A HREF="pthread_mutex_init.html"><B>pthread_mutex_init</B>(3)</A> . +Passing <B>NULL</B> is equivalent to passing a mutex attribute object +with all attributes set to their default values. +</P> +<P><B>pthread_mutexattr_init</B> initializes the mutex attribute +object <I>attr</I> and fills it with default values for the +attributes. +</P> +<P><B>pthread_mutexattr_destroy</B> destroys a mutex attribute +object, which must not be reused until it is reinitialized.</P> +<P>The following mutex types are supported:</P> +<P STYLE="margin-left: 2cm"><B>PTHREAD_MUTEX_NORMAL</B> - for +‘‘fast’’ mutexes.</P> +<P STYLE="margin-left: 2cm"><B>PTHREAD_MUTEX_RECURSIVE</B> - for +‘‘recursive’’ mutexes.</P> +<P STYLE="margin-left: 2cm"><B>PTHREAD_MUTEX_ERRORCHECK</B> - for +‘‘error checking’’ mutexes.</P> +<P>The mutex type determines what happens if a thread attempts to +lock a mutex it already owns with <A HREF="pthread_mutex_lock.html"><B>pthread_mutex_lock</B>(3)</A> +. If the mutex is of the “normal” or “fast” type, +<A HREF="pthread_mutex_lock.html"><B>pthread_mutex_lock</B>(3)</A> +simply suspends the calling thread forever. If the mutex is of the +‘‘error checking’’ type, <A HREF="pthread_mutex_lock.html"><B>pthread_mutex_lock</B>(3)</A> +returns immediately with the error code <B>EDEADLK</B>. If the mutex +is of the ‘‘recursive’’ type, the call to +<A HREF="pthread_mutex_lock.html"><B>pthread_mutex_lock</B>(3)</A> +returns immediately with a success return code. The number of times +the thread owning the mutex has locked it is recorded in the mutex. +The owning thread must call <A HREF="pthread_mutex_unlock.html"><B>pthread_mutex_unlock</B>(3)</A> +the same number of times before the mutex returns to the unlocked +state. +</P> +<P>The default mutex type is <B>PTHREAD_MUTEX_NORMAL</B></P> +<P><B>Pthreads-w32</B> also recognises the following equivalent types +that are used by Linux:</P> +<P STYLE="margin-left: 2cm; font-weight: medium"><B>PTHREAD_MUTEX_FAST_NP</B> +– equivalent to <B>PTHREAD_MUTEX_NORMAL</B></P> +<P STYLE="margin-left: 2cm"><B>PTHREAD_MUTEX_RECURSIVE_NP</B></P> +<P STYLE="margin-left: 2cm"><B>PTHREAD_MUTEX_ERRORCHECK_NP</B></P> +<P><B>pthread_mutexattr_settype</B> sets the mutex type attribute in +<I>attr</I> to the value specified by <I>type</I>. +</P> +<P><B>pthread_mutexattr_gettype</B> retrieves the current value of +the mutex kind attribute in <I>attr</I> and stores it in the location +pointed to by <I>type</I>. +</P> +<P><B>Pthreads-w32</B> also recognises the following equivalent +functions that are used in Linux:</P> +<P><B>pthread_mutexattr_setkind_np</B> is an alias for +<B>pthread_mutexattr_settype</B>. +</P> +<P STYLE="font-weight: medium"><B>pthread_mutexattr_getkind_np</B> is +an alias for <B>pthread_mutexattr_gettype</B>. +</P> +<H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2> +<P><B>pthread_mutexattr_init</B>, <B>pthread_mutexattr_destroy</B> +and <B>pthread_mutexattr_gettype</B> always return 0. +</P> +<P><B>pthread_mutexattr_settype</B> returns 0 on success and a +non-zero error code on error. +</P> +<H2><A HREF="#toc4" NAME="sect4">Errors</A></H2> +<P>On error, <B>pthread_mutexattr_settype</B> returns the following +error code: +</P> +<DL> + <DT><B>EINVAL</B> + </DT><DD STYLE="margin-bottom: 0.5cm"> + <I>type</I> is none of:<BR><B>PTHREAD_MUTEX_NORMAL</B>, + <B>PTHREAD_MUTEX_FAST_NP</B>,<BR><B>PTHREAD_MUTEX_RECURSIVE</B>, + <B>PTHREAD_MUTEX_RECURSIVE_NP,<BR>PTHREAD_MUTEX_ERRORCHECK</B>, + <B>PTHREAD_MUTEX_ERRORCHECK_NP</B> + </DD></DL> +<H2> +<A HREF="#toc5" NAME="sect5">Author</A></H2> +<P>Xavier Leroy <Xavier.Leroy@inria.fr> +</P> +<P>Modified by Ross Johnson for use with <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A>.</P> +<H2><A HREF="#toc6" NAME="sect6">See Also</A></H2> +<P><A HREF="pthread_mutex_init.html"><B>pthread_mutex_init</B>(3)</A> +, <A HREF="pthread_mutex_lock.html"><B>pthread_mutex_lock</B>(3)</A> +, <A HREF="pthread_mutex_unlock.html"><B>pthread_mutex_unlock</B>(3)</A> +. +</P> +<H2><A HREF="#toc7" NAME="sect7"><U><FONT COLOR="#000080">Notes</FONT></U></A></H2> +<P>For speed, <B>Pthreads-w32</B> never checks the thread ownership +of mutexes of type <B>PTHREAD_MUTEX_NORMAL</B> (or +<B>PTHREAD_MUTEX_FAST_NP</B>) when performing operations on the +mutex. It is therefore possible for one thread to lock such a mutex +and another to unlock it.</P> +<P><SPAN STYLE="font-weight: medium">When developing code, it is a +common precaution to substitute the error checking type, and drop in +the normal type for release if the extra performance is required.</SPAN></P> +<HR> +<P><A NAME="toc"></A><B>Table of Contents</B></P> +<UL> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect0" NAME="toc0">Name</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect1" NAME="toc1">Synopsis</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect2" NAME="toc2">Description</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect3" NAME="toc3">Return + Value</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect4" NAME="toc4">Errors</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect5" NAME="toc5">Author</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect6" NAME="toc6">See + Also</A></P> + <LI><P><A HREF="#sect7" NAME="toc7">Notes</A></P> +</UL> +</BODY> +</HTML> |