Mercurial > sdl-ios-xcode
annotate docs/html/sdlsemwait.html @ 1982:3b4ce57c6215
First shot at new audio data types (int32 and float32).
Notable changes:
- Converters between types are autogenerated. Instead of making multiple
passes over the data with seperate filters for endianess, size, signedness,
etc, converting between data types is always one specialized filter. This
simplifies SDL_BuildAudioCVT(), which otherwise had a million edge cases
with the new types, and makes the actually conversions more CPU cache
friendly. Left a stub for adding specific optimized versions of these
routines (SSE/MMX/Altivec, assembler, etc)
- Autogenerated converters are built by SDL/src/audio/sdlgenaudiocvt.pl. This
does not need to be run unless tweaking the code, and thus doesn't need
integration into the build system.
- Went through all the drivers and tried to weed out all the "Uint16"
references that are better specified with the new SDL_AudioFormat typedef.
- Cleaned out a bunch of hardcoded bitwise magic numbers and replaced them
with new SDL_AUDIO_* macros.
- Added initial float32 and int32 support code. Theoretically, existing
drivers will push these through converters to get the data they want to
feed to the hardware.
Still TODO:
- Optimize and debug new converters.
- Update the CoreAudio backend to accept float32 data directly.
- Other backends, too?
- SDL_LoadWAV() needs to be updated to support int32 and float32 .wav files
(both of which exist and can be generated by 'sox' for testing purposes).
- Update the mixer to handle new datatypes.
- Optionally update SDL_sound and SDL_mixer, etc.
author | Ryan C. Gordon <icculus@icculus.org> |
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date | Thu, 24 Aug 2006 12:10:46 +0000 |
parents | 355632dca928 |
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rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_SemWait</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_DestroySemaphore" | |
17 HREF="sdldestroysemaphore.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_SemTryWait" | |
20 HREF="sdlsemtrywait.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="sdldestroysemaphore.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="sdlsemtrywait.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="SDLSEMWAIT" | |
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74 ></A |
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75 >SDL_SemWait</H1 |
0 | 76 ><DIV |
77 CLASS="REFNAMEDIV" | |
78 ><A | |
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79 NAME="AEN8023" |
0 | 80 ></A |
81 ><H2 | |
82 >Name</H2 | |
83 >SDL_SemWait -- Lock a semaphore and suspend the thread if the semaphore value is zero.</DIV | |
84 ><DIV | |
85 CLASS="REFSYNOPSISDIV" | |
86 ><A | |
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87 NAME="AEN8026" |
0 | 88 ></A |
89 ><H2 | |
90 >Synopsis</H2 | |
91 ><DIV | |
92 CLASS="FUNCSYNOPSIS" | |
93 ><A | |
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94 NAME="AEN8027" |
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_SemWait</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="AEN8033" |
0 | 120 ></A |
121 ><H2 | |
122 >Description</H2 | |
123 ><P | |
124 ><TT | |
125 CLASS="FUNCTION" | |
126 >SDL_SemWait()</TT | |
127 > suspends the calling thread until either | |
128 the semaphore pointed to by <TT | |
129 CLASS="PARAMETER" | |
130 ><I | |
131 >sem</I | |
132 ></TT | |
133 > has a positive value, | |
134 the call is interrupted by a signal or error. If the call is successful it | |
135 will atomically decrement the semaphore value.</P | |
136 ><P | |
137 >After <TT | |
138 CLASS="FUNCTION" | |
139 >SDL_SemWait()</TT | |
140 > is successful, the semaphore | |
141 can be released and its count atomically incremented by a successful call to | |
142 <A | |
143 HREF="sdlsempost.html" | |
144 >SDL_SemPost</A | |
145 >.</P | |
146 ></DIV | |
147 ><DIV | |
148 CLASS="REFSECT1" | |
149 ><A | |
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150 NAME="AEN8041" |
0 | 151 ></A |
152 ><H2 | |
153 >Return Value</H2 | |
154 ><P | |
155 >Returns <SPAN | |
156 CLASS="RETURNVALUE" | |
157 >0</SPAN | |
158 > if successful or | |
159 <SPAN | |
160 CLASS="RETURNVALUE" | |
161 >-1</SPAN | |
162 > if there was an error (leaving the semaphore unchanged).</P | |
163 ></DIV | |
164 ><DIV | |
165 CLASS="REFSECT1" | |
166 ><A | |
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167 NAME="AEN8046" |
0 | 168 ></A |
169 ><H2 | |
170 >Examples</H2 | |
171 ><P | |
172 ><PRE | |
173 CLASS="PROGRAMLISTING" | |
174 >if (SDL_SemWait(my_sem) == -1) { | |
175 return WAIT_FAILED; | |
176 } | |
177 | |
178 ... | |
179 | |
180 SDL_SemPost(my_sem);</PRE | |
181 ></P | |
182 ></DIV | |
183 ><DIV | |
184 CLASS="REFSECT1" | |
185 ><A | |
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186 NAME="AEN8050" |
0 | 187 ></A |
188 ><H2 | |
189 >See Also</H2 | |
190 ><P | |
191 ><A | |
192 HREF="sdlcreatesemaphore.html" | |
193 ><TT | |
194 CLASS="FUNCTION" | |
195 >SDL_CreateSemaphore</TT | |
196 ></A | |
197 >, | |
198 <A | |
199 HREF="sdldestroysemaphore.html" | |
200 ><TT | |
201 CLASS="FUNCTION" | |
202 >SDL_DestroySemaphore</TT | |
203 ></A | |
204 >, | |
205 <A | |
206 HREF="sdlsemtrywait.html" | |
207 ><TT | |
208 CLASS="FUNCTION" | |
209 >SDL_SemTryWait</TT | |
210 ></A | |
211 >, | |
212 <A | |
213 HREF="sdlsemwaittimeout.html" | |
214 ><TT | |
215 CLASS="FUNCTION" | |
216 >SDL_SemWaitTimeout</TT | |
217 ></A | |
218 >, | |
219 <A | |
220 HREF="sdlsempost.html" | |
221 ><TT | |
222 CLASS="FUNCTION" | |
223 >SDL_SemPost</TT | |
224 ></A | |
225 >, | |
226 <A | |
227 HREF="sdlsemvalue.html" | |
228 ><TT | |
229 CLASS="FUNCTION" | |
230 >SDL_SemValue</TT | |
231 ></A | |
232 ></P | |
233 ></DIV | |
234 ><DIV | |
235 CLASS="NAVFOOTER" | |
236 ><HR | |
237 ALIGN="LEFT" | |
238 WIDTH="100%"><TABLE | |
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239 SUMMARY="Footer navigation table" |
0 | 240 WIDTH="100%" |
241 BORDER="0" | |
242 CELLPADDING="0" | |
243 CELLSPACING="0" | |
244 ><TR | |
245 ><TD | |
246 WIDTH="33%" | |
247 ALIGN="left" | |
248 VALIGN="top" | |
249 ><A | |
250 HREF="sdldestroysemaphore.html" | |
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251 ACCESSKEY="P" |
0 | 252 >Prev</A |
253 ></TD | |
254 ><TD | |
255 WIDTH="34%" | |
256 ALIGN="center" | |
257 VALIGN="top" | |
258 ><A | |
259 HREF="index.html" | |
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260 ACCESSKEY="H" |
0 | 261 >Home</A |
262 ></TD | |
263 ><TD | |
264 WIDTH="33%" | |
265 ALIGN="right" | |
266 VALIGN="top" | |
267 ><A | |
268 HREF="sdlsemtrywait.html" | |
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269 ACCESSKEY="N" |
0 | 270 >Next</A |
271 ></TD | |
272 ></TR | |
273 ><TR | |
274 ><TD | |
275 WIDTH="33%" | |
276 ALIGN="left" | |
277 VALIGN="top" | |
278 >SDL_DestroySemaphore</TD | |
279 ><TD | |
280 WIDTH="34%" | |
281 ALIGN="center" | |
282 VALIGN="top" | |
283 ><A | |
284 HREF="thread.html" | |
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285 ACCESSKEY="U" |
0 | 286 >Up</A |
287 ></TD | |
288 ><TD | |
289 WIDTH="33%" | |
290 ALIGN="right" | |
291 VALIGN="top" | |
292 >SDL_SemTryWait</TD | |
293 ></TR | |
294 ></TABLE | |
295 ></DIV | |
296 ></BODY | |
297 ></HTML | |
298 > |