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view docs/html/sdlsemwaittimeout.html @ 1550:31c2b8e4885e
Fixed bug #166
From the autoconf obsolete macros documentation:
Macro: AC_CANONICAL_SYSTEM
Determine the system type and set output variables to the names of the canonical system types. See section Getting the Canonical System Type, for details about the variables this macro sets.
The user is encouraged to use either AC_CANONICAL_BUILD, or AC_CANONICAL_HOST, or AC_CANONICAL_TARGET, depending on the needs. Using AC_CANONICAL_TARGET is enough to run the two other macros.
From the documentation for the canonical environments:
case $target in
i386-*-mach* | i386-*-gnu*)
obj_format=aout emulation=mach bfd_gas=yes ;;
i960-*-bout) obj_format=bout ;;
esac
Note that the above example uses $target because it's taken from a tool which can be built on some architecture ($build), run on another ($host), but yet handle data for a third architecture ($target). Such tools are usually part of a compiler suite, they generate code for a specific $target.
However $target should be meaningless for most packages. If you want to base a decision on the system where your program will be run, make sure you use the $host variable.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 19 Mar 2006 05:27:22 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_SemWaitTimeout</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><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 SUMMARY="Header navigation 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" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlsempost.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLSEMWAITTIMEOUT" ></A >SDL_SemWaitTimeout</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN8120" ></A ><H2 >Name</H2 >SDL_SemWaitTimeout -- Lock a semaphore, but only wait up to a specified maximum time.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN8123" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN8124" ></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="AEN8130" ></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="AEN8140" ></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_TIMEDOUT</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="AEN8147" ></A ><H2 >Examples</H2 ><P ><PRE CLASS="PROGRAMLISTING" >res = SDL_SemWaitTimeout(my_sem, WAIT_TIMEOUT_MILLISEC); if (res == SDL_MUTEX_TIMEDOUT) { return TRY_AGAIN; } if (res == -1) { return WAIT_ERROR; } ... SDL_SemPost(my_sem);</PRE ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8151" ></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 SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlsemtrywait.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlsempost.html" ACCESSKEY="N" >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" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_SemPost</TD ></TR ></TABLE ></DIV ></BODY ></HTML >