Mercurial > sdl-ios-xcode
annotate docs/html/sdlcreatemutex.html @ 773:da0a2ad35bf4
Date: Sun, 4 Jan 2004 23:48:19 +0100
From: Max Horn
Subject: Re: Again Audio CD patch
Am 04.01.2004 um 22:38 schrieb Sam Lantinga:
>
> Okay, I fixed the buffering problems by simply using a 4 second buffer
> instead of a 1 second buffer. However, using your code I can't play an
> entire CD - the playback stops after the first song.
>
Found the problem: FSReadFork returns eofErr when the file is finished.
However, we check its return value for errors, and if anything but
noErr occurs, the reader thread aborts its current iteration. That is
bad, because it aborts before it can ever set the flag which tells that
the file is over (also, any remaining data which FSRead did return is
lost - so you'd not hear about to 4 seconds from the end of the file.
Furthermore, the computed data size was 8 bytes to high (I forgot to
account for the fact that the size of an (A)IFF chunk always contains
the chunk header & size fields, too). This is enough to make it work.
However, the end condition is rather fragile, so I tuned some other
things to be pessimistic (check for <= 0 instead of == 0, when eofErr
is encountered enforce mReadFilePosition == mFileLength). You never
know...
The attached patch fixes the issue for me.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Mon, 05 Jan 2004 00:57:51 +0000 |
parents | e5bc29de3f0a |
children | 355632dca928 |
rev | line source |
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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 | |
181
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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 | |
181
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84 NAME="AEN7435" |
0 | 85 ></A |
86 ><H2 | |
87 >Synopsis</H2 | |
88 ><DIV | |
89 CLASS="FUNCSYNOPSIS" | |
90 ><A | |
181
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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 | |
181
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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 | |
181
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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 | |
181
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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 > |