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annotate docs/html/sdlsemtrywait.html @ 1260:80f8c94b5199
Date: 10 Jun 2003 15:30:59 -0400
From: Mike Shal
Subject: [SDL] Bug in SDL_wave.c?
Hey everyone, I'm not sure if this is a bug in SDL, or if I just have
incorrect WAV files. The problem I'm having is loading multiple
concatenated WAVs from SDL_LoadWAV_RW. Some WAV files put comments at
the end of the file (which may be bad form), and SDL doesn't skip past
them when reading from the RWops. So the next WAV I try to load will
start at the comment section of the previous WAV, which obviously
doesn't work. If anyone else is having this problem, one quick fix you
can do is run sox on the bad WAVs, which strips out all of the comment
sections.
Eg:
$ sox sound.wav tmp.wav
$ mv -f tmp.wav sound.wav
The other fix is to patch SDL_wave.c, which is included with this email.
(Assuming I made the patch correctly :). All it does is calculate how
much remaining space there is in the WAV file after the data chunk, and
does SDL_RWseek to skip it. I don't think it should interfere with
anything else, but if someone could check it that would be nice :). If
the bug is really with SDL and not with my WAVs, can someone work this
into the next version of SDL? Thanks,
-Mike Shal
author | Sam Lantinga <slouken@libsdl.org> |
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date | Tue, 24 Jan 2006 07:20:18 +0000 |
parents | 355632dca928 |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_SemTryWait</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="Multi-threaded Programming" | |
14 HREF="thread.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_SemWait" | |
17 HREF="sdlsemwait.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_SemWaitTimeout" | |
20 HREF="sdlsemwaittimeout.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="sdlsemwait.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="sdlsemwaittimeout.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="SDLSEMTRYWAIT" | |
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74 ></A |
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75 >SDL_SemTryWait</H1 |
0 | 76 ><DIV |
77 CLASS="REFNAMEDIV" | |
78 ><A | |
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79 NAME="AEN8069" |
0 | 80 ></A |
81 ><H2 | |
82 >Name</H2 | |
83 >SDL_SemTryWait -- Attempt to lock a semaphore but don't suspend the thread.</DIV | |
84 ><DIV | |
85 CLASS="REFSYNOPSISDIV" | |
86 ><A | |
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87 NAME="AEN8072" |
0 | 88 ></A |
89 ><H2 | |
90 >Synopsis</H2 | |
91 ><DIV | |
92 CLASS="FUNCSYNOPSIS" | |
93 ><A | |
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94 NAME="AEN8073" |
0 | 95 ></A |
96 ><P | |
97 ></P | |
98 ><PRE | |
99 CLASS="FUNCSYNOPSISINFO" | |
100 >#include "SDL.h" | |
101 #include "SDL_thread.h"</PRE | |
102 ><P | |
103 ><CODE | |
104 ><CODE | |
105 CLASS="FUNCDEF" | |
106 >int <B | |
107 CLASS="FSFUNC" | |
108 >SDL_SemTryWait</B | |
109 ></CODE | |
110 >(SDL_sem *sem);</CODE | |
111 ></P | |
112 ><P | |
113 ></P | |
114 ></DIV | |
115 ></DIV | |
116 ><DIV | |
117 CLASS="REFSECT1" | |
118 ><A | |
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119 NAME="AEN8079" |
0 | 120 ></A |
121 ><H2 | |
122 >Description</H2 | |
123 ><P | |
124 ><TT | |
125 CLASS="FUNCTION" | |
126 >SDL_SemTryWait</TT | |
127 > is a non-blocking varient of | |
128 <A | |
129 HREF="sdlsemwait.html" | |
130 ><TT | |
131 CLASS="FUNCTION" | |
132 >SDL_SemWait</TT | |
133 ></A | |
134 >. If the value of the semaphore | |
135 pointed to by <TT | |
136 CLASS="PARAMETER" | |
137 ><I | |
138 >sem</I | |
139 ></TT | |
140 > is positive it will atomically | |
141 decrement the semaphore value and return 0, otherwise it will return | |
142 <SPAN | |
143 CLASS="RETURNVALUE" | |
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144 >SDL_MUTEX_TIMEDOUT</SPAN |
0 | 145 > instead of suspending the thread.</P |
146 ><P | |
147 >After <TT | |
148 CLASS="FUNCTION" | |
149 >SDL_SemTryWait</TT | |
150 > is successful, the semaphore | |
151 can be released and its count atomically incremented by a successful call to | |
152 <A | |
153 HREF="sdlsempost.html" | |
154 >SDL_SemPost</A | |
155 >.</P | |
156 ></DIV | |
157 ><DIV | |
158 CLASS="REFSECT1" | |
159 ><A | |
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160 NAME="AEN8090" |
0 | 161 ></A |
162 ><H2 | |
163 >Return Value</H2 | |
164 ><P | |
165 >Returns <SPAN | |
166 CLASS="RETURNVALUE" | |
167 >0</SPAN | |
168 > if the semaphore was successfully locked or | |
169 either <SPAN | |
170 CLASS="RETURNVALUE" | |
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171 >SDL_MUTEX_TIMEDOUT</SPAN |
0 | 172 > or <SPAN |
173 CLASS="RETURNVALUE" | |
174 >-1</SPAN | |
175 > | |
176 if the thread would have suspended or there was an error, respectivly.</P | |
177 ><P | |
178 >If the semaphore was not successfully locked, the semaphore will be unchanged.</P | |
179 ></DIV | |
180 ><DIV | |
181 CLASS="REFSECT1" | |
182 ><A | |
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183 NAME="AEN8097" |
0 | 184 ></A |
185 ><H2 | |
186 >Examples</H2 | |
187 ><P | |
188 ><PRE | |
189 CLASS="PROGRAMLISTING" | |
190 >res = SDL_SemTryWait(my_sem); | |
191 | |
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192 if (res == SDL_MUTEX_TIMEDOUT) { |
0 | 193 return TRY_AGAIN; |
194 } | |
195 if (res == -1) { | |
196 return WAIT_ERROR; | |
197 } | |
198 | |
199 ... | |
200 | |
201 SDL_SemPost(my_sem);</PRE | |
202 ></P | |
203 ></DIV | |
204 ><DIV | |
205 CLASS="REFSECT1" | |
206 ><A | |
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207 NAME="AEN8101" |
0 | 208 ></A |
209 ><H2 | |
210 >See Also</H2 | |
211 ><P | |
212 ><A | |
213 HREF="sdlcreatesemaphore.html" | |
214 ><TT | |
215 CLASS="FUNCTION" | |
216 >SDL_CreateSemaphore</TT | |
217 ></A | |
218 >, | |
219 <A | |
220 HREF="sdldestroysemaphore.html" | |
221 ><TT | |
222 CLASS="FUNCTION" | |
223 >SDL_DestroySemaphore</TT | |
224 ></A | |
225 >, | |
226 <A | |
227 HREF="sdlsemwait.html" | |
228 ><TT | |
229 CLASS="FUNCTION" | |
230 >SDL_SemWait</TT | |
231 ></A | |
232 >, | |
233 <A | |
234 HREF="sdlsemwaittimeout.html" | |
235 ><TT | |
236 CLASS="FUNCTION" | |
237 >SDL_SemWaitTimeout</TT | |
238 ></A | |
239 >, | |
240 <A | |
241 HREF="sdlsempost.html" | |
242 ><TT | |
243 CLASS="FUNCTION" | |
244 >SDL_SemPost</TT | |
245 ></A | |
246 >, | |
247 <A | |
248 HREF="sdlsemvalue.html" | |
249 ><TT | |
250 CLASS="FUNCTION" | |
251 >SDL_SemValue</TT | |
252 ></A | |
253 ></P | |
254 ></DIV | |
255 ><DIV | |
256 CLASS="NAVFOOTER" | |
257 ><HR | |
258 ALIGN="LEFT" | |
259 WIDTH="100%"><TABLE | |
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260 SUMMARY="Footer navigation table" |
0 | 261 WIDTH="100%" |
262 BORDER="0" | |
263 CELLPADDING="0" | |
264 CELLSPACING="0" | |
265 ><TR | |
266 ><TD | |
267 WIDTH="33%" | |
268 ALIGN="left" | |
269 VALIGN="top" | |
270 ><A | |
271 HREF="sdlsemwait.html" | |
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272 ACCESSKEY="P" |
0 | 273 >Prev</A |
274 ></TD | |
275 ><TD | |
276 WIDTH="34%" | |
277 ALIGN="center" | |
278 VALIGN="top" | |
279 ><A | |
280 HREF="index.html" | |
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281 ACCESSKEY="H" |
0 | 282 >Home</A |
283 ></TD | |
284 ><TD | |
285 WIDTH="33%" | |
286 ALIGN="right" | |
287 VALIGN="top" | |
288 ><A | |
289 HREF="sdlsemwaittimeout.html" | |
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290 ACCESSKEY="N" |
0 | 291 >Next</A |
292 ></TD | |
293 ></TR | |
294 ><TR | |
295 ><TD | |
296 WIDTH="33%" | |
297 ALIGN="left" | |
298 VALIGN="top" | |
299 >SDL_SemWait</TD | |
300 ><TD | |
301 WIDTH="34%" | |
302 ALIGN="center" | |
303 VALIGN="top" | |
304 ><A | |
305 HREF="thread.html" | |
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306 ACCESSKEY="U" |
0 | 307 >Up</A |
308 ></TD | |
309 ><TD | |
310 WIDTH="33%" | |
311 ALIGN="right" | |
312 VALIGN="top" | |
313 >SDL_SemWaitTimeout</TD | |
314 ></TR | |
315 ></TABLE | |
316 ></DIV | |
317 ></BODY | |
318 ></HTML | |
319 > |