Mercurial > sdl-ios-xcode
annotate docs/html/sdlsemtrywait.html @ 641:df178851293b
Date: 28 Jun 2003 22:42:52 +0100
From: Alan Swanson
Subject: Re: [SDL] New XFree 4.3 Video Mode Patch
I have a wee amendment that moves the qsort in set_best_resolution
to only occur after failing to find an exact match only. This would
make absolutely sure we get a user set mode.
While I've never had any problems for my normal resolutions (1280x1024,
1024x768, 800x600 & 640,480) while closely examining the output from
qsort I've noticed it doesn't seem to sort the modes fully. These is
one definite wrong at 1152x768 and a few that just look wrong to me.
From a program (attached) I made to examine this more easily. X has
sorted its mode list using the same method as ours (plus frequency),
and our user modes get inserted without any other movement.
On the patch I've made I've also changed cmpmodes to sort on vertical
resolution and then horizontal. Ie vertical is now most significant
bit.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sat, 28 Jun 2003 21:52:26 +0000 |
| parents | e5bc29de3f0a |
| children | 355632dca928 |
| rev | line source |
|---|---|
| 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 1.64 |
| 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_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 | |
| 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="sdlsemwait.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="sdlsemwaittimeout.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="SDLSEMTRYWAIT" | |
| 71 >SDL_SemTryWait</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN7681" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_SemTryWait -- Attempt to lock a semaphore but don't suspend the thread.</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSYNOPSISDIV" | |
| 83 ><A | |
|
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84 NAME="AEN7684" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Synopsis</H2 | |
| 88 ><DIV | |
| 89 CLASS="FUNCSYNOPSIS" | |
| 90 ><A | |
|
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91 NAME="AEN7685" |
| 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 >int <B | |
| 104 CLASS="FSFUNC" | |
| 105 >SDL_SemTryWait</B | |
| 106 ></CODE | |
| 107 >(SDL_sem *sem);</CODE | |
| 108 ></P | |
| 109 ><P | |
| 110 ></P | |
| 111 ></DIV | |
| 112 ></DIV | |
| 113 ><DIV | |
| 114 CLASS="REFSECT1" | |
| 115 ><A | |
|
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116 NAME="AEN7691" |
| 0 | 117 ></A |
| 118 ><H2 | |
| 119 >Description</H2 | |
| 120 ><P | |
| 121 ><TT | |
| 122 CLASS="FUNCTION" | |
| 123 >SDL_SemTryWait</TT | |
| 124 > is a non-blocking varient of | |
| 125 <A | |
| 126 HREF="sdlsemwait.html" | |
| 127 ><TT | |
| 128 CLASS="FUNCTION" | |
| 129 >SDL_SemWait</TT | |
| 130 ></A | |
| 131 >. If the value of the semaphore | |
| 132 pointed to by <TT | |
| 133 CLASS="PARAMETER" | |
| 134 ><I | |
| 135 >sem</I | |
| 136 ></TT | |
| 137 > is positive it will atomically | |
| 138 decrement the semaphore value and return 0, otherwise it will return | |
| 139 <SPAN | |
| 140 CLASS="RETURNVALUE" | |
| 141 >SDL_MUTEX_TIMEOUT</SPAN | |
| 142 > instead of suspending the thread.</P | |
| 143 ><P | |
| 144 >After <TT | |
| 145 CLASS="FUNCTION" | |
| 146 >SDL_SemTryWait</TT | |
| 147 > is successful, the semaphore | |
| 148 can be released and its count atomically incremented by a successful call to | |
| 149 <A | |
| 150 HREF="sdlsempost.html" | |
| 151 >SDL_SemPost</A | |
| 152 >.</P | |
| 153 ></DIV | |
| 154 ><DIV | |
| 155 CLASS="REFSECT1" | |
| 156 ><A | |
|
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157 NAME="AEN7702" |
| 0 | 158 ></A |
| 159 ><H2 | |
| 160 >Return Value</H2 | |
| 161 ><P | |
| 162 >Returns <SPAN | |
| 163 CLASS="RETURNVALUE" | |
| 164 >0</SPAN | |
| 165 > if the semaphore was successfully locked or | |
| 166 either <SPAN | |
| 167 CLASS="RETURNVALUE" | |
| 168 >SDL_MUTEX_TIMEOUT</SPAN | |
| 169 > or <SPAN | |
| 170 CLASS="RETURNVALUE" | |
| 171 >-1</SPAN | |
| 172 > | |
| 173 if the thread would have suspended or there was an error, respectivly.</P | |
| 174 ><P | |
| 175 >If the semaphore was not successfully locked, the semaphore will be unchanged.</P | |
| 176 ></DIV | |
| 177 ><DIV | |
| 178 CLASS="REFSECT1" | |
| 179 ><A | |
|
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180 NAME="AEN7709" |
| 0 | 181 ></A |
| 182 ><H2 | |
| 183 >Examples</H2 | |
| 184 ><P | |
| 185 ><PRE | |
| 186 CLASS="PROGRAMLISTING" | |
| 187 >res = SDL_SemTryWait(my_sem); | |
| 188 | |
| 189 if (res == SDL_MUTEX_TIMEOUT) { | |
| 190 return TRY_AGAIN; | |
| 191 } | |
| 192 if (res == -1) { | |
| 193 return WAIT_ERROR; | |
| 194 } | |
| 195 | |
| 196 ... | |
| 197 | |
| 198 SDL_SemPost(my_sem);</PRE | |
| 199 ></P | |
| 200 ></DIV | |
| 201 ><DIV | |
| 202 CLASS="REFSECT1" | |
| 203 ><A | |
|
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204 NAME="AEN7713" |
| 0 | 205 ></A |
| 206 ><H2 | |
| 207 >See Also</H2 | |
| 208 ><P | |
| 209 ><A | |
| 210 HREF="sdlcreatesemaphore.html" | |
| 211 ><TT | |
| 212 CLASS="FUNCTION" | |
| 213 >SDL_CreateSemaphore</TT | |
| 214 ></A | |
| 215 >, | |
| 216 <A | |
| 217 HREF="sdldestroysemaphore.html" | |
| 218 ><TT | |
| 219 CLASS="FUNCTION" | |
| 220 >SDL_DestroySemaphore</TT | |
| 221 ></A | |
| 222 >, | |
| 223 <A | |
| 224 HREF="sdlsemwait.html" | |
| 225 ><TT | |
| 226 CLASS="FUNCTION" | |
| 227 >SDL_SemWait</TT | |
| 228 ></A | |
| 229 >, | |
| 230 <A | |
| 231 HREF="sdlsemwaittimeout.html" | |
| 232 ><TT | |
| 233 CLASS="FUNCTION" | |
| 234 >SDL_SemWaitTimeout</TT | |
| 235 ></A | |
| 236 >, | |
| 237 <A | |
| 238 HREF="sdlsempost.html" | |
| 239 ><TT | |
| 240 CLASS="FUNCTION" | |
| 241 >SDL_SemPost</TT | |
| 242 ></A | |
| 243 >, | |
| 244 <A | |
| 245 HREF="sdlsemvalue.html" | |
| 246 ><TT | |
| 247 CLASS="FUNCTION" | |
| 248 >SDL_SemValue</TT | |
| 249 ></A | |
| 250 ></P | |
| 251 ></DIV | |
| 252 ><DIV | |
| 253 CLASS="NAVFOOTER" | |
| 254 ><HR | |
| 255 ALIGN="LEFT" | |
| 256 WIDTH="100%"><TABLE | |
| 257 WIDTH="100%" | |
| 258 BORDER="0" | |
| 259 CELLPADDING="0" | |
| 260 CELLSPACING="0" | |
| 261 ><TR | |
| 262 ><TD | |
| 263 WIDTH="33%" | |
| 264 ALIGN="left" | |
| 265 VALIGN="top" | |
| 266 ><A | |
| 267 HREF="sdlsemwait.html" | |
| 268 >Prev</A | |
| 269 ></TD | |
| 270 ><TD | |
| 271 WIDTH="34%" | |
| 272 ALIGN="center" | |
| 273 VALIGN="top" | |
| 274 ><A | |
| 275 HREF="index.html" | |
| 276 >Home</A | |
| 277 ></TD | |
| 278 ><TD | |
| 279 WIDTH="33%" | |
| 280 ALIGN="right" | |
| 281 VALIGN="top" | |
| 282 ><A | |
| 283 HREF="sdlsemwaittimeout.html" | |
| 284 >Next</A | |
| 285 ></TD | |
| 286 ></TR | |
| 287 ><TR | |
| 288 ><TD | |
| 289 WIDTH="33%" | |
| 290 ALIGN="left" | |
| 291 VALIGN="top" | |
| 292 >SDL_SemWait</TD | |
| 293 ><TD | |
| 294 WIDTH="34%" | |
| 295 ALIGN="center" | |
| 296 VALIGN="top" | |
| 297 ><A | |
| 298 HREF="thread.html" | |
| 299 >Up</A | |
| 300 ></TD | |
| 301 ><TD | |
| 302 WIDTH="33%" | |
| 303 ALIGN="right" | |
| 304 VALIGN="top" | |
| 305 >SDL_SemWaitTimeout</TD | |
| 306 ></TR | |
| 307 ></TABLE | |
| 308 ></DIV | |
| 309 ></BODY | |
| 310 ></HTML | |
| 311 > |