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Catch X11 extension errors...since most of these are notifications that we queried for a missing extension (such as the XiG vidmode one that most people don't have), and default Xlib behaviour is to write notification to stderr, this tends to generate incorrect bug reports. Since we'll actually deal with the missing extension when querying for it, we ignore these errors in our hook. The rest continue to pass through to the default handler. Fixes Bugzilla #42. --ryan.
author Ryan C. Gordon <icculus@icculus.org>
date Sat, 14 Jan 2006 08:15:38 +0000 (2006-01-14)
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
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TITLE="SDL_DestroySemaphore"
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><BODY
CLASS="REFENTRY"
BGCOLOR="#FFF8DC"
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>SDL Library Documentation</TH
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><HR
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WIDTH="100%"></DIV
><H1
><A
NAME="SDLSEMWAIT"
></A
>SDL_SemWait</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN8023"
></A
><H2
>Name</H2
>SDL_SemWait&nbsp;--&nbsp;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
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>Prev</A
></TD
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>Home</A
></TD
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>Next</A
></TD
></TR
><TR
><TD
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>SDL_DestroySemaphore</TD
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>Up</A
></TD
><TD
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