view docs/html/sdlwasinit.html @ 765:4c2ba6161939

Editors Note: The original patch was modified to use SDL_Delay() instead of nanosleep because nanosleep may not be portable to all systems using SDL with the ALSA backend. This may be a moot point with the switch to blocking writes anyway... Date: Sat, 27 Dec 2003 21:47:36 +0100 From: Michel Daenzer To: Debian Bug Tracking System Subject: [SDL] Bug#225252: [PATCH] ALSA fixes Package: libsdl1.2debian-all Version: 1.2.6-2 Severity: normal Tags: patch For SDL 1.2.6, the ALSA backend was changed to call snd_pcm_open() with SND_PCM_NONBLOCK. That's a good idea per se, however, it causes high CPU usage, interrupted sound and stuttering in some games here. Taking a nanosleep whenever snd_pcm_writei() returns -EAGAIN fixes this, but I think it's more efficient to use blocking mode for the actual sound playback. Feedback from the SDL and ALSA lists appreciated. The patch also fixes the default ALSA device to be used.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 04 Jan 2004 15:40:50 +0000
parents e5bc29de3f0a
children 355632dca928
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>SDL_WasInit</A
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><DIV
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><A
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><H2
>Name</H2
>SDL_WasInit&nbsp;--&nbsp;Check which subsystems are initialized</DIV
><DIV
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><H2
>Synopsis</H2
><DIV
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><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>Uint32 <B
CLASS="FSFUNC"
>SDL_WasInit</B
></CODE
>(Uint32 flags);</CODE
></P
><P
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CLASS="REFSECT1"
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NAME="AEN627"
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><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_WasInit</TT
> allows you to see which SDL subsytems have been <A
HREF="sdlinit.html"
>initialized</A
>. <TT
CLASS="PARAMETER"
><I
>flags</I
></TT
> is a bitwise OR'd combination of the subsystems you wish to check (see <A
HREF="sdlinit.html"
><TT
CLASS="FUNCTION"
>SDL_Init</TT
></A
> for a list of subsystem flags).</P
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><H2
>Return Value</H2
><P
><TT
CLASS="FUNCTION"
>SDL_WasInit</TT
> returns a bitwised OR'd combination of the initialized subsystems.</P
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><H2
>Examples</H2
><PRE
CLASS="PROGRAMLISTING"
>&#13;/* Here are several ways you can use SDL_WasInit() */

/* Get init data on all the subsystems */
Uint32 subsystem_init;

subsystem_init=SDL_WasInit(SDL_INIT_EVERYTHING);

if(subsystem_init&#38;SDL_INIT_VIDEO)
  printf("Video is initialized.\n");
else
  printf("Video is not initialized.\n");



/* Just check for one specfic subsystem */

if(SDL_WasInit(SDL_INIT_VIDEO)!=0)
  printf("Video is initialized.\n");
else
  printf("Video is not initialized.\n");




/* Check for two subsystems */

Uint32 subsystem_mask=SDL_INIT_VIDEO|SDL_INIT_AUDIO;

if(SDL_WasInit(subsystem_mask)==subsystem_mask)
  printf("Video and Audio initialized.\n");
else
  printf("Video and Audio not initialized.\n");&#13;</PRE
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>SDL_Init</TT
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>,
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>SDL_Subsystem</TT
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