forked from KolibriOS/kolibrios
295 lines
3.8 KiB
HTML
295 lines
3.8 KiB
HTML
<HTML
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><HEAD
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><TITLE
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>SDL_CreateSemaphore</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.64
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"><LINK
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REL="HOME"
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TITLE="SDL Library Documentation"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="Multi-threaded Programming"
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HREF="thread.html"><LINK
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REL="PREVIOUS"
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TITLE="SDL_mutexV"
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HREF="sdlmutexv.html"><LINK
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REL="NEXT"
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TITLE="SDL_DestroySemaphore"
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HREF="sdldestroysemaphore.html"></HEAD
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><BODY
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CLASS="REFENTRY"
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BGCOLOR="#FFF8DC"
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TEXT="#000000"
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LINK="#0000ee"
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VLINK="#551a8b"
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ALINK="#ff0000"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>SDL Library Documentation</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="sdlmutexv.html"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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></TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="sdldestroysemaphore.html"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><H1
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><A
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NAME="SDLCREATESEMAPHORE"
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>SDL_CreateSemaphore</A
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></H1
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><DIV
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CLASS="REFNAMEDIV"
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><A
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NAME="AEN7387"
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></A
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><H2
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>Name</H2
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>SDL_CreateSemaphore -- Creates a new semaphore and assigns an initial value to it.</DIV
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><DIV
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CLASS="REFSYNOPSISDIV"
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><A
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NAME="AEN7390"
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></A
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><H2
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>Synopsis</H2
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><DIV
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CLASS="FUNCSYNOPSIS"
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><A
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NAME="AEN7391"
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></A
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><P
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></P
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><PRE
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CLASS="FUNCSYNOPSISINFO"
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>#include "SDL.h"
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#include "SDL_thread.h"</PRE
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><P
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><CODE
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><CODE
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CLASS="FUNCDEF"
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>SDL_sem *<B
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CLASS="FSFUNC"
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>SDL_CreateSemaphore</B
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></CODE
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>(Uint32 initial_value);</CODE
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></P
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><P
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></P
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></DIV
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></DIV
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><DIV
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CLASS="REFSECT1"
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><A
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NAME="AEN7397"
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></A
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><H2
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>Description</H2
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><P
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><TT
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CLASS="FUNCTION"
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>SDL_CreateSemaphore()</TT
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> creates a new semaphore and
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initializes it with the value <TT
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CLASS="PARAMETER"
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><I
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>initial_value</I
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></TT
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>.
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Each locking operation on the semaphore by
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<A
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HREF="sdlsemwait.html"
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>SDL_SemWait</A
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>,
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<A
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HREF="sdlsemtrywait.html"
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>SDL_SemTryWait</A
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> or
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<A
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HREF="sdlsemwaittimeout.html"
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>SDL_SemWaitTimeout</A
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>
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will atomically decrement the semaphore value. The locking operation will be blocked
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if the semaphore value is not positive (greater than zero). Each unlock operation by
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<A
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HREF="sdlsempost.html"
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>SDL_SemPost</A
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>
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will atomically increment the semaphore value.</P
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></DIV
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><DIV
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CLASS="REFSECT1"
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><A
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NAME="AEN7406"
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></A
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><H2
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>Return Value</H2
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><P
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>Returns a pointer to an initialized semaphore or
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<SPAN
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CLASS="RETURNVALUE"
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>NULL</SPAN
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> if there was an error.</P
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></DIV
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><DIV
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CLASS="REFSECT1"
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><A
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NAME="AEN7410"
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></A
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><H2
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>Examples</H2
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><P
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><PRE
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CLASS="PROGRAMLISTING"
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>SDL_sem *my_sem;
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my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE);
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if (my_sem == NULL) {
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return CREATE_SEM_FAILED;
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}</PRE
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></P
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></DIV
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><DIV
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CLASS="REFSECT1"
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><A
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NAME="AEN7414"
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></A
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><H2
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>See Also</H2
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><P
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><A
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HREF="sdldestroysemaphore.html"
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><TT
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CLASS="FUNCTION"
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>SDL_DestroySemaphore</TT
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></A
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>,
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<A
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HREF="sdlsemwait.html"
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><TT
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CLASS="FUNCTION"
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>SDL_SemWait</TT
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></A
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>,
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<A
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HREF="sdlsemtrywait.html"
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><TT
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CLASS="FUNCTION"
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>SDL_SemTryWait</TT
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></A
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>,
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<A
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HREF="sdlsemwaittimeout.html"
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><TT
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CLASS="FUNCTION"
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>SDL_SemWaitTimeout</TT
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></A
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>,
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<A
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HREF="sdlsempost.html"
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><TT
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CLASS="FUNCTION"
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>SDL_SemPost</TT
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></A
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>,
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<A
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HREF="sdlsemvalue.html"
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><TT
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CLASS="FUNCTION"
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>SDL_SemValue</TT
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></A
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></P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="sdlmutexv.html"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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HREF="index.html"
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>Home</A
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></TD
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WIDTH="33%"
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HREF="sdldestroysemaphore.html"
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>Next</A
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WIDTH="33%"
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VALIGN="top"
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>SDL_mutexV</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="thread.html"
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>Up</A
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>SDL_DestroySemaphore</TD
|
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></TR
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> |