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view docs/html/sdlcdstatus.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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<HTML ><HEAD ><TITLE >SDL_CDStatus</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_CDOpen" HREF="sdlcdopen.html"><LINK REL="NEXT" TITLE="SDL_CDPlay" HREF="sdlcdplay.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="sdlcdopen.html" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlcdplay.html" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCDSTATUS" >SDL_CDStatus</A ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN6920" ></A ><H2 >Name</H2 >SDL_CDStatus -- Returns the current status of the given drive.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN6923" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN6924" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >CDstatus <B CLASS="FSFUNC" >SDL_CDStatus</B ></CODE >(SDL_CD *cdrom);</CODE ></P ><PRE CLASS="FUNCSYNOPSISINFO" >/* Given a status, returns true if there's a disk in the drive */ #define CD_INDRIVE(status) ((int)status > 0)</PRE ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6931" ></A ><H2 >Description</H2 ><P >This function returns the current status of the given drive. Status is described like so: <PRE CLASS="PROGRAMLISTING" >typedef enum { CD_TRAYEMPTY, CD_STOPPED, CD_PLAYING, CD_PAUSED, CD_ERROR = -1 } CDstatus;</PRE ></P ><P >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.</P ><P >The macro <TT CLASS="LITERAL" >CD_INDRIVE</TT > is provided for convenience, and given a status returns true if there's a disk in the drive.</P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B ><TT CLASS="FUNCTION" >SDL_CDStatus</TT > also updates the <A HREF="sdlcd.html" ><SPAN CLASS="STRUCTNAME" >SDL_CD</SPAN ></A > structure passed to it.</P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6943" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >int 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; }</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6946" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcd.html" ><TT CLASS="FUNCTION" >SDL_CD</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="sdlcdopen.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="sdlcdplay.html" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_CDOpen</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="cdrom.html" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_CDPlay</TD ></TR ></TABLE ></DIV ></BODY ></HTML >