Mercurial > sdl-ios-xcode
annotate docs/html/sdlcdstatus.html @ 968:4675910b0b7b
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> |
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date | Fri, 12 Nov 2004 21:39:04 +0000 |
parents | 355632dca928 |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_CDStatus</TITLE | |
5 ><META | |
6 NAME="GENERATOR" | |
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
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_CDOpen" | |
17 HREF="sdlcdopen.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_CDPlay" | |
20 HREF="sdlcdplay.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 | |
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31 SUMMARY="Header navigation table" |
0 | 32 WIDTH="100%" |
33 BORDER="0" | |
34 CELLPADDING="0" | |
35 CELLSPACING="0" | |
36 ><TR | |
37 ><TH | |
38 COLSPAN="3" | |
39 ALIGN="center" | |
40 >SDL Library Documentation</TH | |
41 ></TR | |
42 ><TR | |
43 ><TD | |
44 WIDTH="10%" | |
45 ALIGN="left" | |
46 VALIGN="bottom" | |
47 ><A | |
48 HREF="sdlcdopen.html" | |
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49 ACCESSKEY="P" |
0 | 50 >Prev</A |
51 ></TD | |
52 ><TD | |
53 WIDTH="80%" | |
54 ALIGN="center" | |
55 VALIGN="bottom" | |
56 ></TD | |
57 ><TD | |
58 WIDTH="10%" | |
59 ALIGN="right" | |
60 VALIGN="bottom" | |
61 ><A | |
62 HREF="sdlcdplay.html" | |
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63 ACCESSKEY="N" |
0 | 64 >Next</A |
65 ></TD | |
66 ></TR | |
67 ></TABLE | |
68 ><HR | |
69 ALIGN="LEFT" | |
70 WIDTH="100%"></DIV | |
71 ><H1 | |
72 ><A | |
73 NAME="SDLCDSTATUS" | |
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74 ></A |
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75 >SDL_CDStatus</H1 |
0 | 76 ><DIV |
77 CLASS="REFNAMEDIV" | |
78 ><A | |
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79 NAME="AEN7308" |
0 | 80 ></A |
81 ><H2 | |
82 >Name</H2 | |
83 >SDL_CDStatus -- Returns the current status of the given drive.</DIV | |
84 ><DIV | |
85 CLASS="REFSYNOPSISDIV" | |
86 ><A | |
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87 NAME="AEN7311" |
0 | 88 ></A |
89 ><H2 | |
90 >Synopsis</H2 | |
91 ><DIV | |
92 CLASS="FUNCSYNOPSIS" | |
93 ><A | |
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94 NAME="AEN7312" |
0 | 95 ></A |
96 ><P | |
97 ></P | |
98 ><PRE | |
99 CLASS="FUNCSYNOPSISINFO" | |
100 >#include "SDL.h"</PRE | |
101 ><P | |
102 ><CODE | |
103 ><CODE | |
104 CLASS="FUNCDEF" | |
105 >CDstatus <B | |
106 CLASS="FSFUNC" | |
107 >SDL_CDStatus</B | |
108 ></CODE | |
109 >(SDL_CD *cdrom);</CODE | |
110 ></P | |
111 ><PRE | |
112 CLASS="FUNCSYNOPSISINFO" | |
113 >/* Given a status, returns true if there's a disk in the drive */ | |
114 #define CD_INDRIVE(status) ((int)status > 0)</PRE | |
115 ><P | |
116 ></P | |
117 ></DIV | |
118 ></DIV | |
119 ><DIV | |
120 CLASS="REFSECT1" | |
121 ><A | |
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122 NAME="AEN7319" |
0 | 123 ></A |
124 ><H2 | |
125 >Description</H2 | |
126 ><P | |
127 >This function returns the current status of the given drive. Status is described like so: | |
128 <PRE | |
129 CLASS="PROGRAMLISTING" | |
130 >typedef enum { | |
131 CD_TRAYEMPTY, | |
132 CD_STOPPED, | |
133 CD_PLAYING, | |
134 CD_PAUSED, | |
135 CD_ERROR = -1 | |
136 } CDstatus;</PRE | |
137 ></P | |
138 ><P | |
139 >If the drive has a CD in it, the table of contents of the CD and current | |
140 play position of the CD will be stored in the SDL_CD structure.</P | |
141 ><P | |
142 >The macro <TT | |
143 CLASS="LITERAL" | |
144 >CD_INDRIVE</TT | |
145 > is provided for convenience, | |
146 and given a status returns true if there's a disk in the drive.</P | |
147 ><DIV | |
148 CLASS="NOTE" | |
149 ><BLOCKQUOTE | |
150 CLASS="NOTE" | |
151 ><P | |
152 ><B | |
153 >Note: </B | |
154 ><TT | |
155 CLASS="FUNCTION" | |
156 >SDL_CDStatus</TT | |
157 > also updates the <A | |
158 HREF="sdlcd.html" | |
159 ><SPAN | |
160 CLASS="STRUCTNAME" | |
161 >SDL_CD</SPAN | |
162 ></A | |
163 > structure passed to it.</P | |
164 ></BLOCKQUOTE | |
165 ></DIV | |
166 ></DIV | |
167 ><DIV | |
168 CLASS="REFSECT1" | |
169 ><A | |
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170 NAME="AEN7331" |
0 | 171 ></A |
172 ><H2 | |
173 >Example</H2 | |
174 ><PRE | |
175 CLASS="PROGRAMLISTING" | |
176 >int playTrack(int track) | |
177 { | |
178 int playing = 0; | |
179 | |
180 if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) { | |
181 /* clamp to the actual number of tracks on the CD */ | |
182 if (track >= cdrom->numtracks) { | |
183 track = cdrom->numtracks-1; | |
184 } | |
185 | |
186 if ( SDL_CDPlayTracks(cdrom, track, 0, 1, 0) == 0 ) { | |
187 playing = 1; | |
188 } | |
189 } | |
190 return playing; | |
191 }</PRE | |
192 ></DIV | |
193 ><DIV | |
194 CLASS="REFSECT1" | |
195 ><A | |
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196 NAME="AEN7334" |
0 | 197 ></A |
198 ><H2 | |
199 >See Also</H2 | |
200 ><P | |
201 ><A | |
202 HREF="sdlcd.html" | |
203 ><TT | |
204 CLASS="FUNCTION" | |
205 >SDL_CD</TT | |
206 ></A | |
207 ></P | |
208 ></DIV | |
209 ><DIV | |
210 CLASS="NAVFOOTER" | |
211 ><HR | |
212 ALIGN="LEFT" | |
213 WIDTH="100%"><TABLE | |
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214 SUMMARY="Footer navigation table" |
0 | 215 WIDTH="100%" |
216 BORDER="0" | |
217 CELLPADDING="0" | |
218 CELLSPACING="0" | |
219 ><TR | |
220 ><TD | |
221 WIDTH="33%" | |
222 ALIGN="left" | |
223 VALIGN="top" | |
224 ><A | |
225 HREF="sdlcdopen.html" | |
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226 ACCESSKEY="P" |
0 | 227 >Prev</A |
228 ></TD | |
229 ><TD | |
230 WIDTH="34%" | |
231 ALIGN="center" | |
232 VALIGN="top" | |
233 ><A | |
234 HREF="index.html" | |
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235 ACCESSKEY="H" |
0 | 236 >Home</A |
237 ></TD | |
238 ><TD | |
239 WIDTH="33%" | |
240 ALIGN="right" | |
241 VALIGN="top" | |
242 ><A | |
243 HREF="sdlcdplay.html" | |
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244 ACCESSKEY="N" |
0 | 245 >Next</A |
246 ></TD | |
247 ></TR | |
248 ><TR | |
249 ><TD | |
250 WIDTH="33%" | |
251 ALIGN="left" | |
252 VALIGN="top" | |
253 >SDL_CDOpen</TD | |
254 ><TD | |
255 WIDTH="34%" | |
256 ALIGN="center" | |
257 VALIGN="top" | |
258 ><A | |
259 HREF="cdrom.html" | |
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260 ACCESSKEY="U" |
0 | 261 >Up</A |
262 ></TD | |
263 ><TD | |
264 WIDTH="33%" | |
265 ALIGN="right" | |
266 VALIGN="top" | |
267 >SDL_CDPlay</TD | |
268 ></TR | |
269 ></TABLE | |
270 ></DIV | |
271 ></BODY | |
272 ></HTML | |
273 > |