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view docs/html/sdlsempost.html @ 3880:74e828c64315 SDL-1.2

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Fixed bug #292 I might be on crack here. It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and right channels of a stereo stream together, and clamps the new mono channel if it would overflow. Shouldn't it be dividing by 2 to average the two sample points instead of clamping? Otherwise the mono sample point's volume doubles in the conversion. This would also make the conversion faster, as it replaces two branches per sample frame with a bitwise shift. --ryan.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 24 Sep 2006 15:45:37 +0000
parents 355632dca928
children
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<HTML
><HEAD
><TITLE
>SDL_SemPost</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
"><LINK
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TITLE="SDL Library Documentation"
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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="SDLSEMPOST"
></A
>SDL_SemPost</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN8170"
></A
><H2
>Name</H2
>SDL_SemPost&nbsp;--&nbsp;Unlock a semaphore.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN8173"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN8174"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"
#include "SDL_thread.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_SemPost</B
></CODE
>(SDL_sem *sem);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8180"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_SemPost</TT
> unlocks the semaphore pointed to by
<TT
CLASS="PARAMETER"
><I
>sem</I
></TT
> and atomically increments the semaphores value.
Threads that were blocking on the semaphore may be scheduled after this call
succeeds.</P
><P
><TT
CLASS="FUNCTION"
>SDL_SemPost</TT
> should be called after a semaphore is locked by a successful call to
<A
HREF="sdlsemwait.html"
>SDL_SemWait</A
>,
<A
HREF="sdlsemtrywait.html"
>SDL_SemTryWait</A
> or
<A
HREF="sdlsemwaittimeout.html"
>SDL_SemWaitTimeout</A
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8190"
></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="AEN8195"
></A
><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>SDL_SemPost(my_sem);</PRE
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8199"
></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="sdlsemwaittimeout.html"
><TT
CLASS="FUNCTION"
>SDL_SemWaitTimeout</TT
></A
>,
<A
HREF="sdlsemvalue.html"
><TT
CLASS="FUNCTION"
>SDL_SemValue</TT
></A
></P
></DIV
><DIV
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><HR
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><A
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>Prev</A
></TD
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><A
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ACCESSKEY="H"
>Home</A
></TD
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><A
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>Next</A
></TD
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><TR
><TD
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>SDL_SemWaitTimeout</TD
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></TD
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>