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view docs/html/sdlsemwaittimeout.html @ 4170:092c0bc69155 SDL-1.2

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Fixed bug #618 Description From Tim Angus 2008-08-30 12:23:56 (-) [reply] As we all know SDL 1.2 doesn't handle dead keys well since one key press potentially equals two (or more) characters. For example, on many layouts, keying <backquote>,<space> results in <no character>,<backquote><space>. Since the unicode member of the SDL_keysym struct only has room for one character, only one can be returned. On Linux, the first character is returned. On Windows however, unless the exact number of characters generated by the keypress is 1, nothing is returned. The following patch addresses this inconsistency. Updated patch which includes a further fix to the handling of the numpad when numlock is on. This further fix is courtesy Amanieu d'Antras.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 13 Apr 2009 08:42:09 +0000
parents 355632dca928
children
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<HTML
><HEAD
><TITLE
>SDL_SemWaitTimeout</TITLE
><META
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>SDL Library Documentation</TH
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><H1
><A
NAME="SDLSEMWAITTIMEOUT"
></A
>SDL_SemWaitTimeout</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN8120"
></A
><H2
>Name</H2
>SDL_SemWaitTimeout&nbsp;--&nbsp;Lock a semaphore, but only wait up to a specified maximum time.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN8123"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN8124"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"
#include "SDL_thread.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_SemWaitTimeout</B
></CODE
>(SDL_sem *sem, Uint32 timeout);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8130"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_SemWaitTimeout()</TT
> is a varient of
<A
HREF="sdlsemwait.html"
>SDL_SemWait</A
>
with a maximum timeout value.
If the value of the semaphore pointed to by <TT
CLASS="PARAMETER"
><I
>sem</I
></TT
> is
positive (greater than zero) it will atomically decrement the semaphore value
and return 0, otherwise it will wait up to <TT
CLASS="PARAMETER"
><I
>timeout</I
></TT
>
milliseconds trying to lock the semaphore. This function is to be avoided if
possible since on some platforms it is implemented by polling the semaphore
every millisecond in a busy loop.</P
><P
>After <TT
CLASS="FUNCTION"
>SDL_SemWaitTimeout()</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="AEN8140"
></A
><H2
>Return Value</H2
><P
>Returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> if the semaphore was successfully locked or
either <SPAN
CLASS="RETURNVALUE"
>SDL_MUTEX_TIMEDOUT</SPAN
> or <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
>
if the timeout period was exceeded or there was an error, respectivly.</P
><P
>If the semaphore was not successfully locked, the semaphore will be unchanged.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8147"
></A
><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>res = SDL_SemWaitTimeout(my_sem, WAIT_TIMEOUT_MILLISEC);

if (res == SDL_MUTEX_TIMEDOUT) {
        return TRY_AGAIN;
}
if (res == -1) {
        return WAIT_ERROR;
}

...

SDL_SemPost(my_sem);</PRE
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8151"
></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="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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