Mercurial > sdl-ios-xcode
annotate docs/html/sdlcreatemutex.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 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_CreateMutex</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="Multi-threaded Programming" | |
| 14 HREF="thread.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="SDL_KillThread" | |
| 17 HREF="sdlkillthread.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_DestroyMutex" | |
| 20 HREF="sdldestroymutex.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="REFENTRY" | |
| 23 BGCOLOR="#FFF8DC" | |
| 24 TEXT="#000000" | |
| 25 LINK="#0000ee" | |
| 26 VLINK="#551a8b" | |
| 27 ALINK="#ff0000" | |
| 28 ><DIV | |
| 29 CLASS="NAVHEADER" | |
| 30 ><TABLE | |
| 31 WIDTH="100%" | |
| 32 BORDER="0" | |
| 33 CELLPADDING="0" | |
| 34 CELLSPACING="0" | |
| 35 ><TR | |
| 36 ><TH | |
| 37 COLSPAN="3" | |
| 38 ALIGN="center" | |
| 39 >SDL Library Documentation</TH | |
| 40 ></TR | |
| 41 ><TR | |
| 42 ><TD | |
| 43 WIDTH="10%" | |
| 44 ALIGN="left" | |
| 45 VALIGN="bottom" | |
| 46 ><A | |
| 47 HREF="sdlkillthread.html" | |
| 48 >Prev</A | |
| 49 ></TD | |
| 50 ><TD | |
| 51 WIDTH="80%" | |
| 52 ALIGN="center" | |
| 53 VALIGN="bottom" | |
| 54 ></TD | |
| 55 ><TD | |
| 56 WIDTH="10%" | |
| 57 ALIGN="right" | |
| 58 VALIGN="bottom" | |
| 59 ><A | |
| 60 HREF="sdldestroymutex.html" | |
| 61 >Next</A | |
| 62 ></TD | |
| 63 ></TR | |
| 64 ></TABLE | |
| 65 ><HR | |
| 66 ALIGN="LEFT" | |
| 67 WIDTH="100%"></DIV | |
| 68 ><H1 | |
| 69 ><A | |
| 70 NAME="SDLCREATEMUTEX" | |
| 71 >SDL_CreateMutex</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN7432" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_CreateMutex -- Create a mutex</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSYNOPSISDIV" | |
| 83 ><A | |
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84 NAME="AEN7435" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Synopsis</H2 | |
| 88 ><DIV | |
| 89 CLASS="FUNCSYNOPSIS" | |
| 90 ><A | |
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91 NAME="AEN7436" |
| 0 | 92 ></A |
| 93 ><P | |
| 94 ></P | |
| 95 ><PRE | |
| 96 CLASS="FUNCSYNOPSISINFO" | |
| 97 >#include "SDL.h" | |
| 98 #include "SDL_thread.h"</PRE | |
| 99 ><P | |
| 100 ><CODE | |
| 101 ><CODE | |
| 102 CLASS="FUNCDEF" | |
| 103 >SDL_mutex *<B | |
| 104 CLASS="FSFUNC" | |
| 105 >SDL_CreateMutex</B | |
| 106 ></CODE | |
| 107 >(void);</CODE | |
| 108 ></P | |
| 109 ><P | |
| 110 ></P | |
| 111 ></DIV | |
| 112 ></DIV | |
| 113 ><DIV | |
| 114 CLASS="REFSECT1" | |
| 115 ><A | |
|
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116 NAME="AEN7442" |
| 0 | 117 ></A |
| 118 ><H2 | |
| 119 >Description</H2 | |
| 120 ><P | |
| 121 >Create a new, unlocked mutex.</P | |
| 122 ></DIV | |
| 123 ><DIV | |
| 124 CLASS="REFSECT1" | |
| 125 ><A | |
|
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126 NAME="AEN7445" |
| 0 | 127 ></A |
| 128 ><H2 | |
| 129 >Examples</H2 | |
| 130 ><PRE | |
| 131 CLASS="PROGRAMLISTING" | |
| 132 >SDL_mutex *mut; | |
| 133 | |
| 134 mut=SDL_CreateMutex(); | |
| 135 . | |
| 136 . | |
| 137 if(SDL_mutexP(mut)==-1){ | |
| 138 fprintf(stderr, "Couldn't lock mutex\n"); | |
| 139 exit(-1); | |
| 140 } | |
| 141 . | |
| 142 /* Do stuff while mutex is locked */ | |
| 143 . | |
| 144 . | |
| 145 if(SDL_mutexV(mut)==-1){ | |
| 146 fprintf(stderr, "Couldn't unlock mutex\n"); | |
| 147 exit(-1); | |
| 148 } | |
| 149 | |
| 150 SDL_DestroyMutex(mut); </PRE | |
| 151 ></DIV | |
| 152 ><DIV | |
| 153 CLASS="REFSECT1" | |
| 154 ><A | |
|
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155 NAME="AEN7448" |
| 0 | 156 ></A |
| 157 ><H2 | |
| 158 >See Also</H2 | |
| 159 ><P | |
| 160 ><A | |
| 161 HREF="sdlmutexp.html" | |
| 162 ><TT | |
| 163 CLASS="FUNCTION" | |
| 164 >SDL_mutexP</TT | |
| 165 ></A | |
| 166 >, | |
| 167 <A | |
| 168 HREF="sdlmutexv.html" | |
| 169 ><TT | |
| 170 CLASS="FUNCTION" | |
| 171 >SDL_mutexV</TT | |
| 172 ></A | |
| 173 >, | |
| 174 <A | |
| 175 HREF="sdldestroymutex.html" | |
| 176 ><TT | |
| 177 CLASS="FUNCTION" | |
| 178 >SDL_DestroyMutex</TT | |
| 179 ></A | |
| 180 ></P | |
| 181 ></DIV | |
| 182 ><DIV | |
| 183 CLASS="NAVFOOTER" | |
| 184 ><HR | |
| 185 ALIGN="LEFT" | |
| 186 WIDTH="100%"><TABLE | |
| 187 WIDTH="100%" | |
| 188 BORDER="0" | |
| 189 CELLPADDING="0" | |
| 190 CELLSPACING="0" | |
| 191 ><TR | |
| 192 ><TD | |
| 193 WIDTH="33%" | |
| 194 ALIGN="left" | |
| 195 VALIGN="top" | |
| 196 ><A | |
| 197 HREF="sdlkillthread.html" | |
| 198 >Prev</A | |
| 199 ></TD | |
| 200 ><TD | |
| 201 WIDTH="34%" | |
| 202 ALIGN="center" | |
| 203 VALIGN="top" | |
| 204 ><A | |
| 205 HREF="index.html" | |
| 206 >Home</A | |
| 207 ></TD | |
| 208 ><TD | |
| 209 WIDTH="33%" | |
| 210 ALIGN="right" | |
| 211 VALIGN="top" | |
| 212 ><A | |
| 213 HREF="sdldestroymutex.html" | |
| 214 >Next</A | |
| 215 ></TD | |
| 216 ></TR | |
| 217 ><TR | |
| 218 ><TD | |
| 219 WIDTH="33%" | |
| 220 ALIGN="left" | |
| 221 VALIGN="top" | |
| 222 >SDL_KillThread</TD | |
| 223 ><TD | |
| 224 WIDTH="34%" | |
| 225 ALIGN="center" | |
| 226 VALIGN="top" | |
| 227 ><A | |
| 228 HREF="thread.html" | |
| 229 >Up</A | |
| 230 ></TD | |
| 231 ><TD | |
| 232 WIDTH="33%" | |
| 233 ALIGN="right" | |
| 234 VALIGN="top" | |
| 235 >SDL_DestroyMutex</TD | |
| 236 ></TR | |
| 237 ></TABLE | |
| 238 ></DIV | |
| 239 ></BODY | |
| 240 ></HTML | |
| 241 > |