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| author | rpj <rpj> | 2005-05-06 07:27:10 +0000 |
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| committer | rpj <rpj> | 2005-05-06 07:27:10 +0000 |
| commit | 7523c7c4d75652f67cd31cb123e1268790394c8b (patch) | |
| tree | 0920ebf089ccb971e0878542f85486171a541a8a /manual/pthread_rwlock_init.html | |
| parent | cf42850c77554311e62d3780f6a36cbc38e5e002 (diff) | |
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diff --git a/manual/pthread_rwlock_init.html b/manual/pthread_rwlock_init.html new file mode 100644 index 0000000..530df93 --- /dev/null +++ b/manual/pthread_rwlock_init.html @@ -0,0 +1,193 @@ +<!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_RWLOCK_DESTROY"(P) manual page</TITLE> + <META NAME="GENERATOR" CONTENT="OpenOffice.org 1.1.3 (Linux)"> + <META NAME="CREATED" CONTENT="20050505;10211800"> + <META NAME="CHANGED" CONTENT="20050505;18563400"> + <!-- manual page source format generated by PolyglotMan v3.2, --> + <!-- available at http://polyglotman.sourceforge.net/ --> +</HEAD> +<BODY LANG="en-GB" BGCOLOR="#ffffff" DIR="LTR"> +<H4>POSIX Threads for Windows – REFERENCE - <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A></H4> +<P><A HREF="index.html">Reference Index</A></P> +<P><A HREF="#toc">Table of Contents</A></P> +<H2><A HREF="#toc0" NAME="sect0">Name</A></H2> +<P>pthread_rwlock_destroy, pthread_rwlock_init - destroy and +initialize a read-write lock object +</P> +<H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2> +<P><B>#include <pthread.h> </B> +</P> +<P><B>pthread_wrlock_t </B><I>rwlock</I> <B>= +PTHREAD_RWLOCK_INITIALIZER;</B></P> +<P><B>int pthread_rwlock_destroy(pthread_rwlock_t *</B><I>rwlock</I><B>); +<BR>int pthread_rwlock_init(pthread_rwlock_t *restrict</B> <I>rwlock</I><B>, +const pthread_rwlockattr_t *restrict</B> <I>attr</I><B>); </B> +</P> +<H2><A HREF="#toc2" NAME="sect2">Description</A></H2> +<P>The <B>pthread_rwlock_destroy</B> function shall destroy the +read-write lock object referenced by <I>rwlock</I> and release any +resources used by the lock. The effect of subsequent use of the lock +is undefined until the lock is reinitialized by another call to +<B>pthread_rwlock_init</B>. An implementation may cause +<B>pthread_rwlock_destroy</B> to set the object referenced by <I>rwlock</I> +to an invalid value. Results are undefined if <B>pthread_rwlock_destroy</B> +is called when any thread holds <I>rwlock</I>. Attempting to destroy +an uninitialized read-write lock results in undefined behavior. +</P> +<P>The <B>pthread_rwlock_init</B> function shall allocate any +resources required to use the read-write lock referenced by <I>rwlock</I> +and initializes the lock to an unlocked state with attributes +referenced by <I>attr</I>. If <I>attr</I> is NULL, the default +read-write lock attributes shall be used; the effect is the same as +passing the address of a default read-write lock attributes object. +Once initialized, the lock can be used any number of times without +being reinitialized. Results are undefined if <B>pthread_rwlock_init</B> +is called specifying an already initialized read-write lock. Results +are undefined if a read-write lock is used without first being +initialized. +</P> +<P>If the <B>pthread_rwlock_init</B> function fails, <I>rwlock</I> +shall not be initialized and the contents of <I>rwlock</I> are +undefined. +</P> +<P><B>Pthreads-w32</B> supports statically initialized <I>rwlock</I> +objects using <B>PTHREAD_RWLOCK_INITIALIZER</B>. <SPAN STYLE="font-weight: medium"> +An application should still call <B>pthread_rwlock_destroy</B> at +some point to ensure that any resources consumed by the read/write +lock are released.</SPAN></P> +<P>Only the object referenced by <I>rwlock</I> may be used for +performing synchronization. The result of referring to copies of that +object in calls to <B>pthread_rwlock_destroy</B> , +<B>pthread_rwlock_rdlock</B> , <B>pthread_rwlock_timedrdlock</B> , +<B>pthread_rwlock_timedwrlock</B> , <B>pthread_rwlock_tryrdlock</B> , +<B>pthread_rwlock_trywrlock</B> , <B>pthread_rwlock_unlock</B> , or +<B>pthread_rwlock_wrlock</B> is undefined. +</P> +<P><B>Pthreads-w32</B> defines <B>_POSIX_READER_WRITER_LOCKS</B> in +pthread.h as 200112L to indicate that the reader/writer routines are +implemented and may be used.</P> +<H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2> +<P>If successful, the <B>pthread_rwlock_destroy</B> and +<B>pthread_rwlock_init</B> functions shall return zero; otherwise, an +error number shall be returned to indicate the error. +</P> +<P>The [EBUSY] and [EINVAL] error checks, if implemented, act as if +they were performed immediately at the beginning of processing for +the function and caused an error return prior to modifying the state +of the read-write lock specified by <I>rwlock</I>. +</P> +<H2><A HREF="#toc4" NAME="sect4">Errors</A></H2> +<P>The <B>pthread_rwlock_destroy</B> function may fail if: +</P> +<DL> + <DT><B>EBUSY</B> + </DT><DD> + The implementation has detected an attempt to destroy the object + referenced by <I>rwlock</I> while it is locked. + </DD><DT> + <B>EINVAL</B> + </DT><DD STYLE="margin-bottom: 0.5cm"> + The value specified by <I>rwlock</I> is invalid. + </DD></DL> +<P> +The <B>pthread_rwlock_init</B> function shall fail if: +</P> +<DL> + <DT><B>EAGAIN</B> + </DT><DD> + The system lacked the necessary resources (other than memory) to + initialize another read-write lock. + </DD><DT> + <B>ENOMEM</B> + </DT><DD> + Insufficient memory exists to initialize the read-write lock. + </DD><DD STYLE="margin-left: 0cm; margin-bottom: 0.5cm"> + <BR><BR> + </DD></DL> +<P> +The <B>pthread_rwlock_init</B> function may fail if: +</P> +<DL> + <DT><B>EINVAL</B> + </DT><DD STYLE="margin-bottom: 0.5cm"> + The value specified by <I>attr</I> is invalid. + </DD></DL> +<P> +These functions shall not return an error code of [EINTR]. +</P> +<P><I>The following sections are informative.</I> +</P> +<H2><A HREF="#toc5" NAME="sect5">Examples</A></H2> +<P>None. +</P> +<H2><A HREF="#toc6" NAME="sect6">Application Usage</A></H2> +<P>Applications using these and related read-write lock functions may +be subject to priority inversion, as discussed in the Base +Definitions volume of IEEE Std 1003.1-2001, Section 3.285, +Priority Inversion. +</P> +<H2><A HREF="#toc7" NAME="sect7">Rationale</A></H2> +<P>None. +</P> +<H2><A HREF="#toc8" NAME="sect8">Future Directions</A></H2> +<P>None. +</P> +<H2><A HREF="#toc9" NAME="sect9">See Also</A></H2> +<P><A HREF="pthread_rwlock_rdlock.html"><B>pthread_rwlock_rdlock</B>(3)</A> +<B>,</B> <A HREF="pthread_rwlock_timedrdlock.html"><B>pthread_rwlock_timedrdlock</B>(3)</A> +<B>,</B> <A HREF="pthread_rwlock_timedwrlock.html"><B>pthread_rwlock_timedwrlock</B>(3)</A> +<B>,</B> <A HREF="pthread_rwlock_rdlock.html"><B>pthread_rwlock_tryrdlock</B>(3)</A> +<B>,</B> <A HREF="pthread_rwlock_wrlock.html"><B>pthread_rwlock_trywrlock</B>(3)</A> +<B>,</B> <A HREF="pthread_rwlock_unlock.html"><B>pthread_rwlock_unlock</B>(3)</A> +<B>,</B> <A HREF="pthread_rwlock_wrlock.html"><B>pthread_rwlock_wrlock</B>(3)</A> +<B>,</B> the Base Definitions volume of IEEE Std 1003.1-2001, +<I><pthread.h></I> +</P> +<H2><A HREF="#toc10" NAME="sect10">Copyright</A></H2> +<P>Portions of this text are reprinted and reproduced in electronic +form from IEEE Std 1003.1, 2003 Edition, Standard for Information +Technology -- Portable Operating System Interface (POSIX), The Open +Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the +Institute of Electrical and Electronics Engineers, Inc and The Open +Group. In the event of any discrepancy between this version and the +original IEEE and The Open Group Standard, the original IEEE and The +Open Group Standard is the referee document. The original Standard +can be obtained online at <A HREF="http://www.opengroup.org/unix/online.html">http://www.opengroup.org/unix/online.html</A> +. +</P> +<P>Modified by Ross Johnson for use with <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A>.</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">Examples</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect6" NAME="toc6">Application + Usage</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect7" NAME="toc7">Rationale</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect8" NAME="toc8">Future + Directions</A> + </P> + <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect9" NAME="toc9">See + Also</A> + </P> + <LI><P><A HREF="#sect10" NAME="toc10">Copyright</A> + </P> +</UL> +</BODY> +</HTML> |