Mercurial > sdl-ios-xcode
view docs/html/general.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 >General</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="SDL Reference" HREF="reference.html"><LINK REL="PREVIOUS" TITLE="SDL Reference" HREF="reference.html"><LINK REL="NEXT" TITLE="SDL_Init" HREF="sdlinit.html"><META NAME="KEYWORD" CONTENT="general"><META NAME="KEYWORD" CONTENT="function"></HEAD ><BODY CLASS="CHAPTER" 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="reference.html" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlinit.html" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="GENERAL" >Chapter 5. General</A ></H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT ><A HREF="sdlinit.html" >SDL_Init</A > — Initializes SDL</DT ><DT ><A HREF="sdlinitsubsystem.html" >SDL_InitSubSystem</A > — Initialize subsystems</DT ><DT ><A HREF="sdlquitsubsystem.html" >SDL_QuitSubSystem</A > — Shut down a subsystem</DT ><DT ><A HREF="sdlquit.html" >SDL_Quit</A > — Shut down SDL</DT ><DT ><A HREF="sdlwasinit.html" >SDL_WasInit</A > — Check which subsystems are initialized</DT ><DT ><A HREF="sdlgeterror.html" >SDL_GetError</A > — Get SDL error string</DT ></DL ></DIV ><P >Before SDL can be used in a program it must be initialized with <A HREF="sdlinit.html" ><TT CLASS="FUNCTION" >SDL_Init</TT ></A >. <TT CLASS="FUNCTION" >SDL_Init</TT > initializes all the subsystems that the user requests (video, audio, joystick, timers and/or cdrom). Once SDL is initialized with <TT CLASS="FUNCTION" >SDL_Init</TT > subsystems can be shut down and initialized as needed using <A HREF="sdlinitsubsystem.html" ><TT CLASS="FUNCTION" >SDL_InitSubSystem</TT ></A > and <A HREF="sdlquitsubsystem.html" ><TT CLASS="FUNCTION" >SDL_QuitSubSystem</TT ></A >.</P ><P >SDL must also be shut down before the program exits to make sure it cleans up correctly. Calling <A HREF="sdlquit.html" ><TT CLASS="FUNCTION" >SDL_Quit</TT ></A > shuts down all subsystems and frees any resources allocated to SDL.</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="reference.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="sdlinit.html" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL Reference</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="reference.html" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_Init</TD ></TR ></TABLE ></DIV ></BODY ></HTML >