Mercurial > sdl-ios-xcode
annotate docs/html/thread.html @ 1555:780fd5b61df1
Fixed bug #89
Date: Sun, 23 Oct 2005 16:39:03 +0200
From: "A. Schmid" <sahib@phreaker.net>
Subject: [SDL] no software surfaces with svgalib driver?
Hi,
I noticed that the SDL (1.2.9) svgalib driver only makes use of linear
addressable (framebuffer) video modes. On older systems (like one of
mine), linear addressable modes are often not available.
Especially for cards with VESA VBE < 2.0 the svgalib vesa driver is
unusable, since VESA only supports framebuffering for VBE 2.0 and later.
The changes necessary to add support for software surfaces seem to be
relatively small. I only had to hack src/video/svga/SDL_svgavideo.c (see
attached patch). The code worked fine for me, but it is no more than a
proof of concept and should be reviewed (probably has a memory leak when
switching modes). It also uses the vgagl library (included in the
svgalib package) and needs to be linked against it.
-Alex
author | Sam Lantinga <slouken@libsdl.org> |
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date | Sun, 19 Mar 2006 12:05:16 +0000 |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >Multi-threaded Programming</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="SDL Reference" | |
14 HREF="reference.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_CDtrack" | |
17 HREF="sdlcdtrack.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_CreateThread" | |
20 HREF="sdlcreatethread.html"><META | |
21 NAME="KEYWORD" | |
22 CONTENT="threads"><META | |
23 NAME="KEYWORD" | |
24 CONTENT="function"></HEAD | |
25 ><BODY | |
26 CLASS="CHAPTER" | |
27 BGCOLOR="#FFF8DC" | |
28 TEXT="#000000" | |
29 LINK="#0000ee" | |
30 VLINK="#551a8b" | |
31 ALINK="#ff0000" | |
32 ><DIV | |
33 CLASS="NAVHEADER" | |
34 ><TABLE | |
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35 SUMMARY="Header navigation table" |
0 | 36 WIDTH="100%" |
37 BORDER="0" | |
38 CELLPADDING="0" | |
39 CELLSPACING="0" | |
40 ><TR | |
41 ><TH | |
42 COLSPAN="3" | |
43 ALIGN="center" | |
44 >SDL Library Documentation</TH | |
45 ></TR | |
46 ><TR | |
47 ><TD | |
48 WIDTH="10%" | |
49 ALIGN="left" | |
50 VALIGN="bottom" | |
51 ><A | |
52 HREF="sdlcdtrack.html" | |
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53 ACCESSKEY="P" |
0 | 54 >Prev</A |
55 ></TD | |
56 ><TD | |
57 WIDTH="80%" | |
58 ALIGN="center" | |
59 VALIGN="bottom" | |
60 ></TD | |
61 ><TD | |
62 WIDTH="10%" | |
63 ALIGN="right" | |
64 VALIGN="bottom" | |
65 ><A | |
66 HREF="sdlcreatethread.html" | |
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67 ACCESSKEY="N" |
0 | 68 >Next</A |
69 ></TD | |
70 ></TR | |
71 ></TABLE | |
72 ><HR | |
73 ALIGN="LEFT" | |
74 WIDTH="100%"></DIV | |
75 ><DIV | |
76 CLASS="CHAPTER" | |
77 ><H1 | |
78 ><A | |
79 NAME="THREAD" | |
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80 ></A |
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81 >Chapter 12. Multi-threaded Programming</H1 |
0 | 82 ><DIV |
83 CLASS="TOC" | |
84 ><DL | |
85 ><DT | |
86 ><B | |
87 >Table of Contents</B | |
88 ></DT | |
89 ><DT | |
90 ><A | |
91 HREF="sdlcreatethread.html" | |
92 >SDL_CreateThread</A | |
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93 > -- Creates a new thread of execution that shares its parent's properties.</DT |
0 | 94 ><DT |
95 ><A | |
96 HREF="sdlthreadid.html" | |
97 >SDL_ThreadID</A | |
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98 > -- Get the 32-bit thread identifier for the current thread.</DT |
0 | 99 ><DT |
100 ><A | |
101 HREF="sdlgetthreadid.html" | |
102 >SDL_GetThreadID</A | |
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103 > -- Get the SDL thread ID of a SDL_Thread</DT |
0 | 104 ><DT |
105 ><A | |
106 HREF="sdlwaitthread.html" | |
107 >SDL_WaitThread</A | |
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108 > -- Wait for a thread to finish.</DT |
0 | 109 ><DT |
110 ><A | |
111 HREF="sdlkillthread.html" | |
112 >SDL_KillThread</A | |
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113 > -- Gracelessly terminates the thread.</DT |
0 | 114 ><DT |
115 ><A | |
116 HREF="sdlcreatemutex.html" | |
117 >SDL_CreateMutex</A | |
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118 > -- Create a mutex</DT |
0 | 119 ><DT |
120 ><A | |
121 HREF="sdldestroymutex.html" | |
122 >SDL_DestroyMutex</A | |
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123 > -- Destroy a mutex</DT |
0 | 124 ><DT |
125 ><A | |
126 HREF="sdlmutexp.html" | |
127 >SDL_mutexP</A | |
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128 > -- Lock a mutex</DT |
0 | 129 ><DT |
130 ><A | |
131 HREF="sdlmutexv.html" | |
132 >SDL_mutexV</A | |
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133 > -- Unlock a mutex</DT |
0 | 134 ><DT |
135 ><A | |
136 HREF="sdlcreatesemaphore.html" | |
137 >SDL_CreateSemaphore</A | |
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138 > -- Creates a new semaphore and assigns an initial value to it.</DT |
0 | 139 ><DT |
140 ><A | |
141 HREF="sdldestroysemaphore.html" | |
142 >SDL_DestroySemaphore</A | |
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143 > -- Destroys a semaphore that was created by <A |
0 | 144 HREF="sdlcreatesemaphore.html" |
145 >SDL_CreateSemaphore</A | |
146 >.</DT | |
147 ><DT | |
148 ><A | |
149 HREF="sdlsemwait.html" | |
150 >SDL_SemWait</A | |
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151 > -- Lock a semaphore and suspend the thread if the semaphore value is zero.</DT |
0 | 152 ><DT |
153 ><A | |
154 HREF="sdlsemtrywait.html" | |
155 >SDL_SemTryWait</A | |
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156 > -- Attempt to lock a semaphore but don't suspend the thread.</DT |
0 | 157 ><DT |
158 ><A | |
159 HREF="sdlsemwaittimeout.html" | |
160 >SDL_SemWaitTimeout</A | |
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161 > -- Lock a semaphore, but only wait up to a specified maximum time.</DT |
0 | 162 ><DT |
163 ><A | |
164 HREF="sdlsempost.html" | |
165 >SDL_SemPost</A | |
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166 > -- Unlock a semaphore.</DT |
0 | 167 ><DT |
168 ><A | |
169 HREF="sdlsemvalue.html" | |
170 >SDL_SemValue</A | |
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171 > -- Return the current value of a semaphore.</DT |
0 | 172 ><DT |
173 ><A | |
174 HREF="sdlcreatecond.html" | |
175 >SDL_CreateCond</A | |
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176 > -- Create a condition variable</DT |
0 | 177 ><DT |
178 ><A | |
179 HREF="sdldestroycond.html" | |
180 >SDL_DestroyCond</A | |
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181 > -- Destroy a condition variable</DT |
0 | 182 ><DT |
183 ><A | |
184 HREF="sdlcondsignal.html" | |
185 >SDL_CondSignal</A | |
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186 > -- Restart a thread wait on a condition variable</DT |
0 | 187 ><DT |
188 ><A | |
189 HREF="sdlcondbroadcast.html" | |
190 >SDL_CondBroadcast</A | |
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191 > -- Restart all threads waiting on a condition variable</DT |
0 | 192 ><DT |
193 ><A | |
194 HREF="sdlcondwait.html" | |
195 >SDL_CondWait</A | |
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196 > -- Wait on a condition variable</DT |
0 | 197 ><DT |
198 ><A | |
199 HREF="sdlcondwaittimeout.html" | |
200 >SDL_CondWaitTimeout</A | |
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201 > -- Wait on a condition variable, with timeout</DT |
0 | 202 ></DL |
203 ></DIV | |
204 ><P | |
205 >SDL provides functions for creating threads, mutexes, semphores and condition variables.</P | |
206 ><P | |
207 >In general, you must be very aware of concurrency and data integrity issues | |
208 when writing multi-threaded programs. Some good guidelines include: | |
209 <P | |
210 ></P | |
211 ><UL | |
212 ><LI | |
213 ><P | |
214 >Don't call SDL video/event functions from separate threads</P | |
215 ></LI | |
216 ><LI | |
217 ><P | |
218 >Don't use any library functions in separate threads</P | |
219 ></LI | |
220 ><LI | |
221 ><P | |
222 >Don't perform any memory management in separate threads</P | |
223 ></LI | |
224 ><LI | |
225 ><P | |
226 >Lock global variables which may be accessed by multiple threads</P | |
227 ></LI | |
228 ><LI | |
229 ><P | |
230 >Never terminate threads, always set a flag and wait for them to quit</P | |
231 ></LI | |
232 ><LI | |
233 ><P | |
234 >Think very carefully about all possible ways your code may interact</P | |
235 ></LI | |
236 ></UL | |
237 ></P | |
238 ><DIV | |
239 CLASS="NOTE" | |
240 ><BLOCKQUOTE | |
241 CLASS="NOTE" | |
242 ><P | |
243 ><B | |
244 >Note: </B | |
181
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245 >SDL's threading is not implemented on MacOS, due to that lack of preemptive thread support (MacOS X dos nt suffer from this problem)</P |
0 | 246 ></BLOCKQUOTE |
247 ></DIV | |
248 ></DIV | |
249 ><DIV | |
250 CLASS="NAVFOOTER" | |
251 ><HR | |
252 ALIGN="LEFT" | |
253 WIDTH="100%"><TABLE | |
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254 SUMMARY="Footer navigation table" |
0 | 255 WIDTH="100%" |
256 BORDER="0" | |
257 CELLPADDING="0" | |
258 CELLSPACING="0" | |
259 ><TR | |
260 ><TD | |
261 WIDTH="33%" | |
262 ALIGN="left" | |
263 VALIGN="top" | |
264 ><A | |
265 HREF="sdlcdtrack.html" | |
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266 ACCESSKEY="P" |
0 | 267 >Prev</A |
268 ></TD | |
269 ><TD | |
270 WIDTH="34%" | |
271 ALIGN="center" | |
272 VALIGN="top" | |
273 ><A | |
274 HREF="index.html" | |
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275 ACCESSKEY="H" |
0 | 276 >Home</A |
277 ></TD | |
278 ><TD | |
279 WIDTH="33%" | |
280 ALIGN="right" | |
281 VALIGN="top" | |
282 ><A | |
283 HREF="sdlcreatethread.html" | |
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284 ACCESSKEY="N" |
0 | 285 >Next</A |
286 ></TD | |
287 ></TR | |
288 ><TR | |
289 ><TD | |
290 WIDTH="33%" | |
291 ALIGN="left" | |
292 VALIGN="top" | |
293 >SDL_CDtrack</TD | |
294 ><TD | |
295 WIDTH="34%" | |
296 ALIGN="center" | |
297 VALIGN="top" | |
298 ><A | |
299 HREF="reference.html" | |
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300 ACCESSKEY="U" |
0 | 301 >Up</A |
302 ></TD | |
303 ><TD | |
304 WIDTH="33%" | |
305 ALIGN="right" | |
306 VALIGN="top" | |
307 >SDL_CreateThread</TD | |
308 ></TR | |
309 ></TABLE | |
310 ></DIV | |
311 ></BODY | |
312 ></HTML | |
313 > |