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Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST) From: Hannu Savolainen Subject: Re: SDL uses obsolete OSS features I did some work on getting OSS to work better with SDL. There have been some problems with select which should be fixed now. I'm having some problems in understanding what is the purpose of the DSP_WaitAudio() routine. I added a return to the very beginning of this routine and commendted out the define for USE_BLOCKING_WRITES. At least lbreakout2 seems to work as well as earlier. The latencies are the same. An ordinary blocking write does exactly the same thing than DSP_WaitAudio does. So I would recommend using the USE_BLOCKING_WRITES approach and removing everything from the DSP_WaitAudio routine. Also enabling USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because you don't need to handle the partial writes (the do-while loop). Attached is a patch against SDL-1.2.7. After these changes SDL will use OSS as it's designed to be used (make it as simple as possible). This code should work with all OSS implementations because it uses only the very fundamental features that have been there since the jurassic times.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 12 Nov 2004 21:39:04 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_CDStatus" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_CDStatus\- Returns the current status of the given drive\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBCDstatus \fBSDL_CDStatus\fP\fR(\fBSDL_CD *cdrom\fR);
\fB/* Given a status, returns true if there\&'s a disk in the drive */
#define CD_INDRIVE(status)      ((int)status > 0)
.SH "DESCRIPTION"
.PP
This function returns the current status of the given drive\&. Status is described like so: 
.PP
.nf
\f(CWtypedef enum {
  CD_TRAYEMPTY,
  CD_STOPPED,
  CD_PLAYING,
  CD_PAUSED,
  CD_ERROR = -1
} CDstatus;\fR
.fi
.PP
.PP
If the drive has a CD in it, the table of contents of the CD and current play position of the CD will be stored in the SDL_CD structure\&.
.PP
The macro \fBCD_INDRIVE\fP is provided for convenience, and given a status returns true if there\&'s a disk in the drive\&.
.PP
.RS
\fBNote:  
.PP
\fBSDL_CDStatus\fP also updates the \fI\fBSDL_CD\fR\fR structure passed to it\&.
.RE
.SH "EXAMPLE"
.PP
.nf
\f(CWint playTrack(int track)
{
  int playing = 0;

  if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) {
  /* clamp to the actual number of tracks on the CD */
    if (track >= cdrom->numtracks) {
      track = cdrom->numtracks-1;
    }

    if ( SDL_CDPlayTracks(cdrom, track, 0, 1, 0) == 0 ) {
      playing = 1;
    }
  }
  return playing;
}\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_CD\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58