Mercurial > sdl-ios-xcode
view docs/html/sdlcreatesemaphore.html @ 1643:51038e80ae59
More general fix for bug #189
The clipping is done at a higher level, and the low level functions are
passed clipped rectangles. Drivers which don't support source clipping
have not been changed, so the image will be squished instead of clipped,
but at least they will no longer crash when the destination rect was out
of bounds.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 17 Apr 2006 06:47:23 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_CreateSemaphore</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_mutexV" HREF="sdlmutexv.html"><LINK REL="NEXT" TITLE="SDL_DestroySemaphore" HREF="sdldestroysemaphore.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="sdlmutexv.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdldestroysemaphore.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCREATESEMAPHORE" ></A >SDL_CreateSemaphore</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN7936" ></A ><H2 >Name</H2 >SDL_CreateSemaphore -- Creates a new semaphore and assigns an initial value to it.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN7939" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN7940" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h" #include "SDL_thread.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_sem *<B CLASS="FSFUNC" >SDL_CreateSemaphore</B ></CODE >(Uint32 initial_value);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7946" ></A ><H2 >Description</H2 ><P ><TT CLASS="FUNCTION" >SDL_CreateSemaphore()</TT > creates a new semaphore and initializes it with the value <TT CLASS="PARAMETER" ><I >initial_value</I ></TT >. Each locking operation on the semaphore by <A HREF="sdlsemwait.html" >SDL_SemWait</A >, <A HREF="sdlsemtrywait.html" >SDL_SemTryWait</A > or <A HREF="sdlsemwaittimeout.html" >SDL_SemWaitTimeout</A > will atomically decrement the semaphore value. The locking operation will be blocked if the semaphore value is not positive (greater than zero). Each unlock operation by <A HREF="sdlsempost.html" >SDL_SemPost</A > will atomically increment the semaphore value.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7955" ></A ><H2 >Return Value</H2 ><P >Returns a pointer to an initialized semaphore or <SPAN CLASS="RETURNVALUE" >NULL</SPAN > if there was an error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7959" ></A ><H2 >Examples</H2 ><P ><PRE CLASS="PROGRAMLISTING" >SDL_sem *my_sem; my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE); if (my_sem == NULL) { return CREATE_SEM_FAILED; }</PRE ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7963" ></A ><H2 >See Also</H2 ><P ><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="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="sdlmutexv.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="sdldestroysemaphore.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_mutexV</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_DestroySemaphore</TD ></TR ></TABLE ></DIV ></BODY ></HTML >