view docs/html/sdlcdopen.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
line wrap: on
line source

<HTML
><HEAD
><TITLE
>SDL_CDOpen</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.64
"><LINK
REL="HOME"
TITLE="SDL Library Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="CD-ROM"
HREF="cdrom.html"><LINK
REL="PREVIOUS"
TITLE="SDL_CDName"
HREF="sdlcdname.html"><LINK
REL="NEXT"
TITLE="SDL_CDStatus"
HREF="sdlcdstatus.html"></HEAD
><BODY
CLASS="REFENTRY"
BGCOLOR="#FFF8DC"
TEXT="#000000"
LINK="#0000ee"
VLINK="#551a8b"
ALINK="#ff0000"
><DIV
CLASS="NAVHEADER"
><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="sdlcdname.html"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdlcdstatus.html"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="SDLCDOPEN"
>SDL_CDOpen</A
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN6886"
></A
><H2
>Name</H2
>SDL_CDOpen&nbsp;--&nbsp;Opens a CD-ROM drive for access.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN6889"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN6890"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>SDL_CD *<B
CLASS="FSFUNC"
>SDL_CDOpen</B
></CODE
>(int drive);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6896"
></A
><H2
>Description</H2
><P
>Opens a CD-ROM drive for access.  It returns a <A
HREF="sdlcd.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_CD</SPAN
></A
> structure on success, or <TT
CLASS="LITERAL"
>NULL</TT
> if the drive was invalid or busy.  This newly opened CD-ROM becomes the default CD used when other CD functions are passed a <TT
CLASS="LITERAL"
>NULL</TT
> CD-ROM handle. </P
><P
>Drives are numbered starting with 0.  
Drive 0 is the system default CD-ROM.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6904"
></A
><H2
>Examples</H2
><PRE
CLASS="PROGRAMLISTING"
>SDL_CD *cdrom;
int cur_track;
int min, sec, frame;
SDL_Init(SDL_INIT_CDROM);
atexit(SDL_Quit);

/* Check for CD drives */
if(!SDL_CDNumDrives()){
  /* None found */
  fprintf(stderr, "No CDROM devices available\n");
  exit(-1);
}

/* Open the default drive */
cdrom=SDL_CDOpen(0);

/* Did if open? Check if cdrom is NULL */
if(!cdrom){
  fprintf(stderr, "Couldn't open drive: %s\n", SDL_GetError());
  exit(-1);
}

/* Print Volume info */
printf("Name: %s\n", SDL_CDName(0));
printf("Tracks: %d\n", cdrom-&#62;numtracks);
for(cur_track=0;cur_track &#60; cdrom-&#62;numtracks; cur_track++){
  FRAMES_TO_MSF(cdrom-&#62;track[cur_track].length, &#38;min, &#38;sec, &#38;frame);
  printf("\tTrack %d: Length %d:%d\n", cur_track, min, sec);
}

SDL_CDClose(cdrom);</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6907"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlcd.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_CD</SPAN
></A
>,
<A
HREF="sdlcdtrack.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_CDtrack</SPAN
></A
>,
<A
HREF="sdlcdclose.html"
><TT
CLASS="FUNCTION"
>SDL_CDClose</TT
></A
></P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="sdlcdname.html"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="sdlcdstatus.html"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_CDName</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="cdrom.html"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>SDL_CDStatus</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>