Mercurial > sdl-ios-xcode

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

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
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
line wrap: on
line source

<HTML
><HEAD
><TITLE
>SDL_SemTryWait</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_SemWait"
HREF="sdlsemwait.html"><LINK
REL="NEXT"
TITLE="SDL_SemWaitTimeout"
HREF="sdlsemwaittimeout.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="sdlsemwait.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdlsemwaittimeout.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="SDLSEMTRYWAIT"
></A
>SDL_SemTryWait</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN8069"
></A
><H2
>Name</H2
>SDL_SemTryWait&nbsp;--&nbsp;Attempt to lock a semaphore but don't suspend the thread.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN8072"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN8073"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"
#include "SDL_thread.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_SemTryWait</B
></CODE
>(SDL_sem *sem);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8079"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_SemTryWait</TT
> is a non-blocking varient of
<A
HREF="sdlsemwait.html"
><TT
CLASS="FUNCTION"
>SDL_SemWait</TT
></A
>. If the value of the semaphore
pointed to by <TT
CLASS="PARAMETER"
><I
>sem</I
></TT
> is positive it will atomically
decrement the semaphore value and return 0, otherwise it will return
<SPAN
CLASS="RETURNVALUE"
>SDL_MUTEX_TIMEDOUT</SPAN
> instead of suspending the thread.</P
><P
>After <TT
CLASS="FUNCTION"
>SDL_SemTryWait</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="AEN8090"
></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 thread would have suspended 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="AEN8097"
></A
><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>res = SDL_SemTryWait(my_sem);

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="AEN8101"
></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="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="sdlsemwait.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="sdlsemwaittimeout.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_SemWait</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_SemWaitTimeout</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>