Mercurial > sdl-ios-xcode
annotate 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 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_CDOpen</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="CD-ROM" | |
| 14 HREF="cdrom.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="SDL_CDName" | |
| 17 HREF="sdlcdname.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_CDStatus" | |
| 20 HREF="sdlcdstatus.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="sdlcdname.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="sdlcdstatus.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="SDLCDOPEN" | |
| 71 >SDL_CDOpen</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN6886" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_CDOpen -- Opens a CD-ROM drive for access.</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSYNOPSISDIV" | |
| 83 ><A | |
|
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84 NAME="AEN6889" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Synopsis</H2 | |
| 88 ><DIV | |
| 89 CLASS="FUNCSYNOPSIS" | |
| 90 ><A | |
|
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91 NAME="AEN6890" |
| 0 | 92 ></A |
| 93 ><P | |
| 94 ></P | |
| 95 ><PRE | |
| 96 CLASS="FUNCSYNOPSISINFO" | |
| 97 >#include "SDL.h"</PRE | |
| 98 ><P | |
| 99 ><CODE | |
| 100 ><CODE | |
| 101 CLASS="FUNCDEF" | |
| 102 >SDL_CD *<B | |
| 103 CLASS="FSFUNC" | |
| 104 >SDL_CDOpen</B | |
| 105 ></CODE | |
| 106 >(int drive);</CODE | |
| 107 ></P | |
| 108 ><P | |
| 109 ></P | |
| 110 ></DIV | |
| 111 ></DIV | |
| 112 ><DIV | |
| 113 CLASS="REFSECT1" | |
| 114 ><A | |
|
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115 NAME="AEN6896" |
| 0 | 116 ></A |
| 117 ><H2 | |
| 118 >Description</H2 | |
| 119 ><P | |
| 120 >Opens a CD-ROM drive for access. It returns a <A | |
| 121 HREF="sdlcd.html" | |
| 122 ><SPAN | |
| 123 CLASS="STRUCTNAME" | |
| 124 >SDL_CD</SPAN | |
| 125 ></A | |
| 126 > structure on success, or <TT | |
| 127 CLASS="LITERAL" | |
| 128 >NULL</TT | |
| 129 > 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 | |
| 130 CLASS="LITERAL" | |
| 131 >NULL</TT | |
| 132 > CD-ROM handle. </P | |
| 133 ><P | |
| 134 >Drives are numbered starting with 0. | |
| 135 Drive 0 is the system default CD-ROM.</P | |
| 136 ></DIV | |
| 137 ><DIV | |
| 138 CLASS="REFSECT1" | |
| 139 ><A | |
|
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140 NAME="AEN6904" |
| 0 | 141 ></A |
| 142 ><H2 | |
| 143 >Examples</H2 | |
| 144 ><PRE | |
| 145 CLASS="PROGRAMLISTING" | |
| 146 >SDL_CD *cdrom; | |
| 147 int cur_track; | |
| 148 int min, sec, frame; | |
| 149 SDL_Init(SDL_INIT_CDROM); | |
| 150 atexit(SDL_Quit); | |
| 151 | |
| 152 /* Check for CD drives */ | |
| 153 if(!SDL_CDNumDrives()){ | |
| 154 /* None found */ | |
| 155 fprintf(stderr, "No CDROM devices available\n"); | |
| 156 exit(-1); | |
| 157 } | |
| 158 | |
| 159 /* Open the default drive */ | |
| 160 cdrom=SDL_CDOpen(0); | |
| 161 | |
| 162 /* Did if open? Check if cdrom is NULL */ | |
| 163 if(!cdrom){ | |
| 164 fprintf(stderr, "Couldn't open drive: %s\n", SDL_GetError()); | |
| 165 exit(-1); | |
| 166 } | |
| 167 | |
| 168 /* Print Volume info */ | |
| 169 printf("Name: %s\n", SDL_CDName(0)); | |
| 170 printf("Tracks: %d\n", cdrom->numtracks); | |
| 171 for(cur_track=0;cur_track < cdrom->numtracks; cur_track++){ | |
| 172 FRAMES_TO_MSF(cdrom->track[cur_track].length, &min, &sec, &frame); | |
| 173 printf("\tTrack %d: Length %d:%d\n", cur_track, min, sec); | |
| 174 } | |
| 175 | |
| 176 SDL_CDClose(cdrom);</PRE | |
| 177 ></DIV | |
| 178 ><DIV | |
| 179 CLASS="REFSECT1" | |
| 180 ><A | |
|
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181 NAME="AEN6907" |
| 0 | 182 ></A |
| 183 ><H2 | |
| 184 >See Also</H2 | |
| 185 ><P | |
| 186 ><A | |
| 187 HREF="sdlcd.html" | |
| 188 ><SPAN | |
| 189 CLASS="STRUCTNAME" | |
| 190 >SDL_CD</SPAN | |
| 191 ></A | |
| 192 >, | |
| 193 <A | |
| 194 HREF="sdlcdtrack.html" | |
| 195 ><SPAN | |
| 196 CLASS="STRUCTNAME" | |
| 197 >SDL_CDtrack</SPAN | |
| 198 ></A | |
| 199 >, | |
| 200 <A | |
| 201 HREF="sdlcdclose.html" | |
| 202 ><TT | |
| 203 CLASS="FUNCTION" | |
| 204 >SDL_CDClose</TT | |
| 205 ></A | |
| 206 ></P | |
| 207 ></DIV | |
| 208 ><DIV | |
| 209 CLASS="NAVFOOTER" | |
| 210 ><HR | |
| 211 ALIGN="LEFT" | |
| 212 WIDTH="100%"><TABLE | |
| 213 WIDTH="100%" | |
| 214 BORDER="0" | |
| 215 CELLPADDING="0" | |
| 216 CELLSPACING="0" | |
| 217 ><TR | |
| 218 ><TD | |
| 219 WIDTH="33%" | |
| 220 ALIGN="left" | |
| 221 VALIGN="top" | |
| 222 ><A | |
| 223 HREF="sdlcdname.html" | |
| 224 >Prev</A | |
| 225 ></TD | |
| 226 ><TD | |
| 227 WIDTH="34%" | |
| 228 ALIGN="center" | |
| 229 VALIGN="top" | |
| 230 ><A | |
| 231 HREF="index.html" | |
| 232 >Home</A | |
| 233 ></TD | |
| 234 ><TD | |
| 235 WIDTH="33%" | |
| 236 ALIGN="right" | |
| 237 VALIGN="top" | |
| 238 ><A | |
| 239 HREF="sdlcdstatus.html" | |
| 240 >Next</A | |
| 241 ></TD | |
| 242 ></TR | |
| 243 ><TR | |
| 244 ><TD | |
| 245 WIDTH="33%" | |
| 246 ALIGN="left" | |
| 247 VALIGN="top" | |
| 248 >SDL_CDName</TD | |
| 249 ><TD | |
| 250 WIDTH="34%" | |
| 251 ALIGN="center" | |
| 252 VALIGN="top" | |
| 253 ><A | |
| 254 HREF="cdrom.html" | |
| 255 >Up</A | |
| 256 ></TD | |
| 257 ><TD | |
| 258 WIDTH="33%" | |
| 259 ALIGN="right" | |
| 260 VALIGN="top" | |
| 261 >SDL_CDStatus</TD | |
| 262 ></TR | |
| 263 ></TABLE | |
| 264 ></DIV | |
| 265 ></BODY | |
| 266 ></HTML | |
| 267 > |