Mercurial > sdl-ios-xcode
annotate docs/html/sdlsettimer.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_SetTimer</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="Time" | |
14 HREF="time.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_RemoveTimer" | |
17 HREF="sdlremovetimer.html"></HEAD | |
18 ><BODY | |
19 CLASS="REFENTRY" | |
20 BGCOLOR="#FFF8DC" | |
21 TEXT="#000000" | |
22 LINK="#0000ee" | |
23 VLINK="#551a8b" | |
24 ALINK="#ff0000" | |
25 ><DIV | |
26 CLASS="NAVHEADER" | |
27 ><TABLE | |
28 WIDTH="100%" | |
29 BORDER="0" | |
30 CELLPADDING="0" | |
31 CELLSPACING="0" | |
32 ><TR | |
33 ><TH | |
34 COLSPAN="3" | |
35 ALIGN="center" | |
36 >SDL Library Documentation</TH | |
37 ></TR | |
38 ><TR | |
39 ><TD | |
40 WIDTH="10%" | |
41 ALIGN="left" | |
42 VALIGN="bottom" | |
43 ><A | |
44 HREF="sdlremovetimer.html" | |
45 >Prev</A | |
46 ></TD | |
47 ><TD | |
48 WIDTH="80%" | |
49 ALIGN="center" | |
50 VALIGN="bottom" | |
51 ></TD | |
52 ><TD | |
53 WIDTH="10%" | |
54 ALIGN="right" | |
55 VALIGN="bottom" | |
56 > </TD | |
57 ></TR | |
58 ></TABLE | |
59 ><HR | |
60 ALIGN="LEFT" | |
61 WIDTH="100%"></DIV | |
62 ><H1 | |
63 ><A | |
64 NAME="SDLSETTIMER" | |
65 >SDL_SetTimer</A | |
66 ></H1 | |
67 ><DIV | |
68 CLASS="REFNAMEDIV" | |
69 ><A | |
181
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70 NAME="AEN8169" |
0 | 71 ></A |
72 ><H2 | |
73 >Name</H2 | |
74 >SDL_SetTimer -- Set a callback to run after the specified number of milliseconds has | |
75 elapsed.</DIV | |
76 ><DIV | |
77 CLASS="REFSYNOPSISDIV" | |
78 ><A | |
181
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79 NAME="AEN8172" |
0 | 80 ></A |
81 ><H2 | |
82 >Synopsis</H2 | |
83 ><DIV | |
84 CLASS="FUNCSYNOPSIS" | |
85 ><A | |
181
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86 NAME="AEN8173" |
0 | 87 ></A |
88 ><P | |
89 ></P | |
90 ><PRE | |
91 CLASS="FUNCSYNOPSISINFO" | |
92 >#include "SDL.h"</PRE | |
93 ><P | |
94 ><CODE | |
95 ><CODE | |
96 CLASS="FUNCDEF" | |
97 >int <B | |
98 CLASS="FSFUNC" | |
99 >SDL_SetTimer</B | |
100 ></CODE | |
101 >(Uint32 interval, SDL_TimerCallback callback);</CODE | |
102 ></P | |
103 ><P | |
104 ></P | |
105 ></DIV | |
106 ></DIV | |
107 ><DIV | |
108 CLASS="REFSECT1" | |
109 ><A | |
110 NAME="SDLTIMERCALLBACK" | |
111 ></A | |
112 ><H2 | |
113 >Callback</H2 | |
114 ><P | |
115 >/* Function prototype for the timer callback function */ | |
116 typedef Uint32 (*SDL_TimerCallback)(Uint32 interval);</P | |
117 ></DIV | |
118 ><DIV | |
119 CLASS="REFSECT1" | |
120 ><A | |
181
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121 NAME="AEN8182" |
0 | 122 ></A |
123 ><H2 | |
124 >Description</H2 | |
125 ><P | |
126 >Set a callback to run after the specified number of milliseconds has | |
127 elapsed. The callback function is passed the current timer interval | |
128 and returns the next timer interval. If the returned value is the | |
129 same as the one passed in, the periodic alarm continues, otherwise a | |
130 new alarm is scheduled.</P | |
131 ><P | |
132 >To cancel a currently running timer, call | |
133 <TT | |
134 CLASS="FUNCTION" | |
135 >SDL_SetTimer(0, NULL);</TT | |
136 ></P | |
137 ><P | |
138 >The timer callback function may run in a different thread than your | |
139 main constant, and so shouldn't call any functions from within itself.</P | |
140 ><P | |
141 >The maximum resolution of this timer is 10 ms, which means that if | |
142 you request a 16 ms timer, your callback will run approximately 20 ms | |
143 later on an unloaded system. If you wanted to set a flag signaling | |
144 a frame update at 30 frames per second (every 33 ms), you might set a | |
145 timer for 30 ms (see example below).</P | |
146 ><P | |
147 >If you use this function, you need to pass <TT | |
148 CLASS="LITERAL" | |
149 >SDL_INIT_TIMER</TT | |
150 > | |
151 to <TT | |
152 CLASS="FUNCTION" | |
153 >SDL_Init()</TT | |
154 >.</P | |
155 ><DIV | |
156 CLASS="NOTE" | |
157 ><BLOCKQUOTE | |
158 CLASS="NOTE" | |
159 ><P | |
160 ><B | |
161 >Note: </B | |
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162 >This function is kept for compatibility but has been superseded |
0 | 163 by the new timer functions |
164 <A | |
165 HREF="sdladdtimer.html" | |
166 >SDL_AddTimer</A | |
167 > and | |
168 <A | |
169 HREF="sdlremovetimer.html" | |
170 >SDL_RemoveTimer</A | |
171 > which support | |
172 multiple timers.</P | |
173 ></BLOCKQUOTE | |
174 ></DIV | |
175 ></DIV | |
176 ><DIV | |
177 CLASS="REFSECT1" | |
178 ><A | |
181
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179 NAME="AEN8196" |
0 | 180 ></A |
181 ><H2 | |
182 >Examples</H2 | |
183 ><P | |
184 ><PRE | |
185 CLASS="PROGRAMLISTING" | |
186 >SDL_SetTimer((33/10)*10, my_callback);</PRE | |
187 ></P | |
188 ></DIV | |
189 ><DIV | |
190 CLASS="REFSECT1" | |
191 ><A | |
181
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192 NAME="AEN8200" |
0 | 193 ></A |
194 ><H2 | |
195 >See Also</H2 | |
196 ><P | |
197 ><A | |
198 HREF="sdladdtimer.html" | |
199 ><TT | |
200 CLASS="FUNCTION" | |
201 >SDL_AddTimer</TT | |
202 ></A | |
203 ></P | |
204 ></DIV | |
205 ><DIV | |
206 CLASS="NAVFOOTER" | |
207 ><HR | |
208 ALIGN="LEFT" | |
209 WIDTH="100%"><TABLE | |
210 WIDTH="100%" | |
211 BORDER="0" | |
212 CELLPADDING="0" | |
213 CELLSPACING="0" | |
214 ><TR | |
215 ><TD | |
216 WIDTH="33%" | |
217 ALIGN="left" | |
218 VALIGN="top" | |
219 ><A | |
220 HREF="sdlremovetimer.html" | |
221 >Prev</A | |
222 ></TD | |
223 ><TD | |
224 WIDTH="34%" | |
225 ALIGN="center" | |
226 VALIGN="top" | |
227 ><A | |
228 HREF="index.html" | |
229 >Home</A | |
230 ></TD | |
231 ><TD | |
232 WIDTH="33%" | |
233 ALIGN="right" | |
234 VALIGN="top" | |
235 > </TD | |
236 ></TR | |
237 ><TR | |
238 ><TD | |
239 WIDTH="33%" | |
240 ALIGN="left" | |
241 VALIGN="top" | |
242 >SDL_RemoveTimer</TD | |
243 ><TD | |
244 WIDTH="34%" | |
245 ALIGN="center" | |
246 VALIGN="top" | |
247 ><A | |
248 HREF="time.html" | |
249 >Up</A | |
250 ></TD | |
251 ><TD | |
252 WIDTH="33%" | |
253 ALIGN="right" | |
254 VALIGN="top" | |
255 > </TD | |
256 ></TR | |
257 ></TABLE | |
258 ></DIV | |
259 ></BODY | |
260 ></HTML | |
261 > |