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

Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children 55f1f1b3e27d
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+++ b/docs/html/sdlsemwaittimeout.html	Thu Apr 26 16:45:43 2001 +0000
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+<HTML
+><HEAD
+><TITLE
+>SDL_SemWaitTimeout</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_SemTryWait"
+HREF="sdlsemtrywait.html"><LINK
+REL="NEXT"
+TITLE="SDL_SemPost"
+HREF="sdlsempost.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="sdlsemtrywait.html"
+>Prev</A
+></TD
+><TD
+WIDTH="80%"
+ALIGN="center"
+VALIGN="bottom"
+></TD
+><TD
+WIDTH="10%"
+ALIGN="right"
+VALIGN="bottom"
+><A
+HREF="sdlsempost.html"
+>Next</A
+></TD
+></TR
+></TABLE
+><HR
+ALIGN="LEFT"
+WIDTH="100%"></DIV
+><H1
+><A
+NAME="SDLSEMWAITTIMEOUT"
+>SDL_SemWaitTimeout</A
+></H1
+><DIV
+CLASS="REFNAMEDIV"
+><A
+NAME="AEN7495"
+></A
+><H2
+>Name</H2
+>SDL_SemWaitTimeout&nbsp;--&nbsp;Lock a semaphore, but only wait up to a specified maximum time.</DIV
+><DIV
+CLASS="REFSYNOPSISDIV"
+><A
+NAME="AEN7498"
+></A
+><H2
+>Synopsis</H2
+><DIV
+CLASS="FUNCSYNOPSIS"
+><A
+NAME="AEN7499"
+></A
+><P
+></P
+><PRE
+CLASS="FUNCSYNOPSISINFO"
+>#include "SDL.h"
+#include "SDL_thread.h"</PRE
+><P
+><CODE
+><CODE
+CLASS="FUNCDEF"
+>int <B
+CLASS="FSFUNC"
+>SDL_SemWaitTimeout</B
+></CODE
+>(SDL_sem *sem, Uint32 timeout);</CODE
+></P
+><P
+></P
+></DIV
+></DIV
+><DIV
+CLASS="REFSECT1"
+><A
+NAME="AEN7505"
+></A
+><H2
+>Description</H2
+><P
+><TT
+CLASS="FUNCTION"
+>SDL_SemWaitTimeout()</TT
+> is a varient of
+<A
+HREF="sdlsemwait.html"
+>SDL_SemWait</A
+>
+with a maximum timeout value.
+If the value of the semaphore pointed to by <TT
+CLASS="PARAMETER"
+><I
+>sem</I
+></TT
+> is
+positive (greater than zero) it will atomically decrement the semaphore value
+and return 0, otherwise it will wait up to <TT
+CLASS="PARAMETER"
+><I
+>timeout</I
+></TT
+>
+milliseconds trying to lock the semaphore. This function is to be avoided if
+possible since on some platforms it is implemented by polling the semaphore
+every millisecond in a busy loop.</P
+><P
+>After <TT
+CLASS="FUNCTION"
+>SDL_SemWaitTimeout()</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="AEN7515"
+></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 timeout period was exceeded 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="AEN7522"
+></A
+><H2
+>Examples</H2
+><P
+><PRE
+CLASS="PROGRAMLISTING"
+>res = SDL_SemWaitTimeout(my_sem, WAIT_TIMEOUT_MILLISEC);
+
+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="AEN7526"
+></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="sdlsemtrywait.html"
+><TT
+CLASS="FUNCTION"
+>SDL_SemTryWait</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="sdlsemtrywait.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="sdlsempost.html"
+>Next</A
+></TD
+></TR
+><TR
+><TD
+WIDTH="33%"
+ALIGN="left"
+VALIGN="top"
+>SDL_SemTryWait</TD
+><TD
+WIDTH="34%"
+ALIGN="center"
+VALIGN="top"
+><A
+HREF="thread.html"
+>Up</A
+></TD
+><TD
+WIDTH="33%"
+ALIGN="right"
+VALIGN="top"
+>SDL_SemPost</TD
+></TR
+></TABLE
+></DIV
+></BODY
+></HTML
+>
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