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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_spin_init.html | |
| parent | cf42850c77554311e62d3780f6a36cbc38e5e002 (diff) | |
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diff --git a/manual/pthread_spin_init.html b/manual/pthread_spin_init.html new file mode 100644 index 0000000..35e657b --- /dev/null +++ b/manual/pthread_spin_init.html @@ -0,0 +1,176 @@ +<!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_SPIN_DESTROY"(P) manual page</TITLE> + <META NAME="GENERATOR" CONTENT="OpenOffice.org 1.1.3 (Linux)"> + <META NAME="CREATED" CONTENT="20050505;12074100"> + <META NAME="CHANGED" CONTENT="20050505;19014200"> + <!-- 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_spin_destroy, pthread_spin_init - destroy or initialize a +spin lock object (<B>ADVANCED REALTIME THREADS</B>) +</P> +<H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2> +<P><B>#include <pthread.h> </B> +</P> +<P><B>pthread_spinlock_t</B> <I>lock</I> <B>= +PTHREAD_SPINLOCK_INITIALIZER;</B></P> +<P><B>int pthread_spin_destroy(pthread_spinlock_t *</B><I>lock</I><B>); +<BR>int pthread_spin_init(pthread_spinlock_t *</B><I>lock</I><B>, int</B> +<I>pshared</I><B>); </B> +</P> +<H2><A HREF="#toc2" NAME="sect2">Description</A></H2> +<P>The <B>pthread_spin_destroy</B> function shall destroy the spin +lock referenced by <I>lock</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_spin_init</B> . +The results are undefined if <B>pthread_spin_destroy</B> is called +when a thread holds the lock, or if this function is called with an +uninitialized thread spin lock. +</P> +<P>The <B>pthread_spin_init</B> function shall allocate any resources +required to use the spin lock referenced by <I>lock</I> and +initialize the lock to an unlocked state. +</P> +<P><B>Pthreads-w32</B> supports single and multiple processor systems +as well as process CPU affinity masking by checking the mask when the +spin lock is initialized. If the process is using only a single +processor at the time <B>pthread_spin_init</B> is called then the +spin lock is initialized as a PTHREAD_MUTEX_NORMAL mutex object. A +thread that calls <A HREF="pthread_spin_lock.html"><B>pthread_spin_lock(3)</B></A> +will block rather than spin in this case. If the process CPU affinity +mask is altered after the spin lock has been initialised, the spin +lock is not modified, and may no longer be optimal for the number of +CPUs available.</P> +<P><B>Pthreads-w32</B> defines <B>_POSIX_THREAD_PROCESS_SHARED</B> in +pthread.h as -1 to indicate that these routines do not support the +<B>PTHREAD_PROCESS_SHARED</B> attribute. <B>pthread_spin_init</B> +will return the error <B>ENOTSUP</B> if the value of <I>pshared</I> +is not <B>PTHREAD_PROCESS_PRIVATE</B>.</P> +<P>The results are undefined if <B>pthread_spin_init</B> is called +specifying an already initialized spin lock. The results are +undefined if a spin lock is used without first being initialized. +</P> +<P>If the <B>pthread_spin_init</B> function fails, the lock is not +initialized and the contents of <I>lock</I> are undefined. +</P> +<P>Only the object referenced by <I>lock</I> may be used for +performing synchronization. +</P> +<P>The result of referring to copies of that object in calls to +<B>pthread_spin_destroy</B> , <A HREF="pthread_spin_lock.html"><B>pthread_spin_lock</B>(3)</A> +, <A HREF="pthread_spin_lock.html"><B>pthread_spin_trylock</B>(3)</A>, +or <A HREF="pthread_spin_unlock.html"><B>pthread_spin_unlock</B>(3)</A> +is undefined. +</P> +<P><B>Pthreads-w32</B> supports statically initialized spin locks +using <B>PTHREAD_SPINLOCK_INITIALIZER</B>. An application should +still call <B>pthread_spin_destroy</B> at some point to ensure that +any resources consumed by the spin lock are released.</P> +<H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2> +<P>Upon successful completion, these functions shall return zero; +otherwise, an error number shall be returned to indicate the error. +</P> +<H2><A HREF="#toc4" NAME="sect4">Errors</A></H2> +<P>These functions may fail if: +</P> +<DL> + <DT><B>EBUSY</B> + </DT><DD> + The implementation has detected an attempt to initialize or destroy + a spin lock while it is in use (for example, while being used in a + <A HREF="pthread_spin_lock.html"><B>pthread_spin_lock</B>(3)</A> + call) by another thread. + </DD><DT> + <B>EINVAL</B> + </DT><DD STYLE="margin-bottom: 0.5cm"> + The value specified by <I>lock</I> is invalid. + </DD></DL> +<P> +The <B>pthread_spin_init</B> function shall fail if: +</P> +<DL> + <DT><B>ENOTSUP</B> + </DT><DD> + The value of <I>pshared</I> is not <B>PTHREAD_PROCESS_PRIVATE</B>.</DD><DT> + <B>ENOMEM</B> + </DT><DD STYLE="margin-bottom: 0.5cm"> + Insufficient memory exists to initialize the lock. + </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>The <B>pthread_spin_destroy</B> and <B>pthread_spin_init</B> +functions are part of the Spin Locks option and need not be provided +on all implementations. +</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_spin_lock.html"><B>pthread_spin_lock</B>(3)</A> <B>,</B> +<A HREF="pthread_spin_unlock.html"><B>pthread_spin_unlock</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> |