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diff docs/html/sdlsemtrywait.html @ 0:74212992fb08

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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children 55f1f1b3e27d
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/docs/html/sdlsemtrywait.html	Thu Apr 26 16:45:43 2001 +0000
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+<HTML
+><HEAD
+><TITLE
+>SDL_SemTryWait</TITLE
+><META
+NAME="GENERATOR"
+CONTENT="Modular DocBook HTML Stylesheet Version 1.61
+"><LINK
+REL="HOME"
+TITLE="SDL Library Documentation"
+HREF="index.html"><LINK
+REL="UP"
+TITLE="Multi-threaded Programming"
+HREF="thread.html"><LINK
+REL="PREVIOUS"
+TITLE="SDL_SemWait"
+HREF="sdlsemwait.html"><LINK
+REL="NEXT"
+TITLE="SDL_SemWaitTimeout"
+HREF="sdlsemwaittimeout.html"></HEAD
+><BODY
+CLASS="REFENTRY"
+BGCOLOR="#FFF8DC"
+TEXT="#000000"
+LINK="#0000ee"
+VLINK="#551a8b"
+ALINK="#ff0000"
+><DIV
+CLASS="NAVHEADER"
+><TABLE
+WIDTH="100%"
+BORDER="0"
+CELLPADDING="0"
+CELLSPACING="0"
+><TR
+><TH
+COLSPAN="3"
+ALIGN="center"
+>SDL Library Documentation</TH
+></TR
+><TR
+><TD
+WIDTH="10%"
+ALIGN="left"
+VALIGN="bottom"
+><A
+HREF="sdlsemwait.html"
+>Prev</A
+></TD
+><TD
+WIDTH="80%"
+ALIGN="center"
+VALIGN="bottom"
+></TD
+><TD
+WIDTH="10%"
+ALIGN="right"
+VALIGN="bottom"
+><A
+HREF="sdlsemwaittimeout.html"
+>Next</A
+></TD
+></TR
+></TABLE
+><HR
+ALIGN="LEFT"
+WIDTH="100%"></DIV
+><H1
+><A
+NAME="SDLSEMTRYWAIT"
+>SDL_SemTryWait</A
+></H1
+><DIV
+CLASS="REFNAMEDIV"
+><A
+NAME="AEN7444"
+></A
+><H2
+>Name</H2
+>SDL_SemTryWait&nbsp;--&nbsp;Attempt to lock a semaphore but don't suspend the thread.</DIV
+><DIV
+CLASS="REFSYNOPSISDIV"
+><A
+NAME="AEN7447"
+></A
+><H2
+>Synopsis</H2
+><DIV
+CLASS="FUNCSYNOPSIS"
+><A
+NAME="AEN7448"
+></A
+><P
+></P
+><PRE
+CLASS="FUNCSYNOPSISINFO"
+>#include "SDL.h"
+#include "SDL_thread.h"</PRE
+><P
+><CODE
+><CODE
+CLASS="FUNCDEF"
+>int <B
+CLASS="FSFUNC"
+>SDL_SemTryWait</B
+></CODE
+>(SDL_sem *sem);</CODE
+></P
+><P
+></P
+></DIV
+></DIV
+><DIV
+CLASS="REFSECT1"
+><A
+NAME="AEN7454"
+></A
+><H2
+>Description</H2
+><P
+><TT
+CLASS="FUNCTION"
+>SDL_SemTryWait</TT
+> is a non-blocking varient of
+<A
+HREF="sdlsemwait.html"
+><TT
+CLASS="FUNCTION"
+>SDL_SemWait</TT
+></A
+>. If the value of the semaphore
+pointed to by <TT
+CLASS="PARAMETER"
+><I
+>sem</I
+></TT
+> is positive it will atomically
+decrement the semaphore value and return 0, otherwise it will return
+<SPAN
+CLASS="RETURNVALUE"
+>SDL_MUTEX_TIMEOUT</SPAN
+> instead of suspending the thread.</P
+><P
+>After <TT
+CLASS="FUNCTION"
+>SDL_SemTryWait</TT
+> is successful, the semaphore
+can be released and its count atomically incremented by a successful call to
+<A
+HREF="sdlsempost.html"
+>SDL_SemPost</A
+>.</P
+></DIV
+><DIV
+CLASS="REFSECT1"
+><A
+NAME="AEN7465"
+></A
+><H2
+>Return Value</H2
+><P
+>Returns <SPAN
+CLASS="RETURNVALUE"
+>0</SPAN
+> if the semaphore was successfully locked or
+either <SPAN
+CLASS="RETURNVALUE"
+>SDL_MUTEX_TIMEOUT</SPAN
+> or <SPAN
+CLASS="RETURNVALUE"
+>-1</SPAN
+>
+if the thread would have suspended or there was an error, respectivly.</P
+><P
+>If the semaphore was not successfully locked, the semaphore will be unchanged.</P
+></DIV
+><DIV
+CLASS="REFSECT1"
+><A
+NAME="AEN7472"
+></A
+><H2
+>Examples</H2
+><P
+><PRE
+CLASS="PROGRAMLISTING"
+>res = SDL_SemTryWait(my_sem);
+
+if (res == SDL_MUTEX_TIMEOUT) {
+        return TRY_AGAIN;
+}
+if (res == -1) {
+        return WAIT_ERROR;
+}
+
+...
+
+SDL_SemPost(my_sem);</PRE
+></P
+></DIV
+><DIV
+CLASS="REFSECT1"
+><A
+NAME="AEN7476"
+></A
+><H2
+>See Also</H2
+><P
+><A
+HREF="sdlcreatesemaphore.html"
+><TT
+CLASS="FUNCTION"
+>SDL_CreateSemaphore</TT
+></A
+>,
+<A
+HREF="sdldestroysemaphore.html"
+><TT
+CLASS="FUNCTION"
+>SDL_DestroySemaphore</TT
+></A
+>,
+<A
+HREF="sdlsemwait.html"
+><TT
+CLASS="FUNCTION"
+>SDL_SemWait</TT
+></A
+>,
+<A
+HREF="sdlsemwaittimeout.html"
+><TT
+CLASS="FUNCTION"
+>SDL_SemWaitTimeout</TT
+></A
+>,
+<A
+HREF="sdlsempost.html"
+><TT
+CLASS="FUNCTION"
+>SDL_SemPost</TT
+></A
+>,
+<A
+HREF="sdlsemvalue.html"
+><TT
+CLASS="FUNCTION"
+>SDL_SemValue</TT
+></A
+></P
+></DIV
+><DIV
+CLASS="NAVFOOTER"
+><HR
+ALIGN="LEFT"
+WIDTH="100%"><TABLE
+WIDTH="100%"
+BORDER="0"
+CELLPADDING="0"
+CELLSPACING="0"
+><TR
+><TD
+WIDTH="33%"
+ALIGN="left"
+VALIGN="top"
+><A
+HREF="sdlsemwait.html"
+>Prev</A
+></TD
+><TD
+WIDTH="34%"
+ALIGN="center"
+VALIGN="top"
+><A
+HREF="index.html"
+>Home</A
+></TD
+><TD
+WIDTH="33%"
+ALIGN="right"
+VALIGN="top"
+><A
+HREF="sdlsemwaittimeout.html"
+>Next</A
+></TD
+></TR
+><TR
+><TD
+WIDTH="33%"
+ALIGN="left"
+VALIGN="top"
+>SDL_SemWait</TD
+><TD
+WIDTH="34%"
+ALIGN="center"
+VALIGN="top"
+><A
+HREF="thread.html"
+>Up</A
+></TD
+><TD
+WIDTH="33%"
+ALIGN="right"
+VALIGN="top"
+>SDL_SemWaitTimeout</TD
+></TR
+></TABLE
+></DIV
+></BODY
+></HTML
+>
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