Mercurial > sdl-ios-xcode
view docs/html/sdlsemwait.html @ 2947:fec0db6c44b7
Date: Thu, 01 Jan 2009 21:32:12 +0100
From: Couriersud
Subject: Fusionsound audio driver
attached is a diff containing a audio driver for the FusionSound
library. This sound library is closely related to DirectFB and uses the
same transport (fusion) as DirectFB when running applications "remote",
i.e. over the network. As such, it natively redirects sound where
DirectFB redirects video. This may be handy for everyone using SDL over
DirectFB.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Thu, 01 Jan 2009 21:34:22 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_SemWait</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_DestroySemaphore" HREF="sdldestroysemaphore.html"><LINK REL="NEXT" TITLE="SDL_SemTryWait" HREF="sdlsemtrywait.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="sdldestroysemaphore.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlsemtrywait.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLSEMWAIT" ></A >SDL_SemWait</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN8023" ></A ><H2 >Name</H2 >SDL_SemWait -- Lock a semaphore and suspend the thread if the semaphore value is zero.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN8026" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN8027" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h" #include "SDL_thread.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_SemWait</B ></CODE >(SDL_sem *sem);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8033" ></A ><H2 >Description</H2 ><P ><TT CLASS="FUNCTION" >SDL_SemWait()</TT > suspends the calling thread until either the semaphore pointed to by <TT CLASS="PARAMETER" ><I >sem</I ></TT > has a positive value, the call is interrupted by a signal or error. If the call is successful it will atomically decrement the semaphore value.</P ><P >After <TT CLASS="FUNCTION" >SDL_SemWait()</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="AEN8041" ></A ><H2 >Return Value</H2 ><P >Returns <SPAN CLASS="RETURNVALUE" >0</SPAN > if successful or <SPAN CLASS="RETURNVALUE" >-1</SPAN > if there was an error (leaving the semaphore unchanged).</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8046" ></A ><H2 >Examples</H2 ><P ><PRE CLASS="PROGRAMLISTING" >if (SDL_SemWait(my_sem) == -1) { return WAIT_FAILED; } ... SDL_SemPost(my_sem);</PRE ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8050" ></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="sdlsemtrywait.html" ><TT CLASS="FUNCTION" >SDL_SemTryWait</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 SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdldestroysemaphore.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="sdlsemtrywait.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_DestroySemaphore</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_SemTryWait</TD ></TR ></TABLE ></DIV ></BODY ></HTML >