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annotate docs/html/sdlsemwaittimeout.html @ 665:d27aab66c5d6
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| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Wed, 06 Aug 2003 20:12:00 +0000 |
| parents | e5bc29de3f0a |
| children | 355632dca928 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_SemWaitTimeout</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_SemTryWait" | |
| 17 HREF="sdlsemtrywait.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_SemPost" | |
| 20 HREF="sdlsempost.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="sdlsemtrywait.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="sdlsempost.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="SDLSEMWAITTIMEOUT" | |
| 71 >SDL_SemWaitTimeout</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN7732" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_SemWaitTimeout -- Lock a semaphore, but only wait up to a specified maximum time.</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSYNOPSISDIV" | |
| 83 ><A | |
|
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84 NAME="AEN7735" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Synopsis</H2 | |
| 88 ><DIV | |
| 89 CLASS="FUNCSYNOPSIS" | |
| 90 ><A | |
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91 NAME="AEN7736" |
| 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_SemWaitTimeout</B | |
| 106 ></CODE | |
| 107 >(SDL_sem *sem, Uint32 timeout);</CODE | |
| 108 ></P | |
| 109 ><P | |
| 110 ></P | |
| 111 ></DIV | |
| 112 ></DIV | |
| 113 ><DIV | |
| 114 CLASS="REFSECT1" | |
| 115 ><A | |
|
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116 NAME="AEN7742" |
| 0 | 117 ></A |
| 118 ><H2 | |
| 119 >Description</H2 | |
| 120 ><P | |
| 121 ><TT | |
| 122 CLASS="FUNCTION" | |
| 123 >SDL_SemWaitTimeout()</TT | |
| 124 > is a varient of | |
| 125 <A | |
| 126 HREF="sdlsemwait.html" | |
| 127 >SDL_SemWait</A | |
| 128 > | |
| 129 with a maximum timeout value. | |
| 130 If the value of the semaphore pointed to by <TT | |
| 131 CLASS="PARAMETER" | |
| 132 ><I | |
| 133 >sem</I | |
| 134 ></TT | |
| 135 > is | |
| 136 positive (greater than zero) it will atomically decrement the semaphore value | |
| 137 and return 0, otherwise it will wait up to <TT | |
| 138 CLASS="PARAMETER" | |
| 139 ><I | |
| 140 >timeout</I | |
| 141 ></TT | |
| 142 > | |
| 143 milliseconds trying to lock the semaphore. This function is to be avoided if | |
| 144 possible since on some platforms it is implemented by polling the semaphore | |
| 145 every millisecond in a busy loop.</P | |
| 146 ><P | |
| 147 >After <TT | |
| 148 CLASS="FUNCTION" | |
| 149 >SDL_SemWaitTimeout()</TT | |
| 150 > is successful, the semaphore | |
| 151 can be released and its count atomically incremented by a successful call to | |
| 152 <A | |
| 153 HREF="sdlsempost.html" | |
| 154 >SDL_SemPost</A | |
| 155 >.</P | |
| 156 ></DIV | |
| 157 ><DIV | |
| 158 CLASS="REFSECT1" | |
| 159 ><A | |
|
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160 NAME="AEN7752" |
| 0 | 161 ></A |
| 162 ><H2 | |
| 163 >Return Value</H2 | |
| 164 ><P | |
| 165 >Returns <SPAN | |
| 166 CLASS="RETURNVALUE" | |
| 167 >0</SPAN | |
| 168 > if the semaphore was successfully locked or | |
| 169 either <SPAN | |
| 170 CLASS="RETURNVALUE" | |
| 171 >SDL_MUTEX_TIMEOUT</SPAN | |
| 172 > or <SPAN | |
| 173 CLASS="RETURNVALUE" | |
| 174 >-1</SPAN | |
| 175 > | |
| 176 if the timeout period was exceeded or there was an error, respectivly.</P | |
| 177 ><P | |
| 178 >If the semaphore was not successfully locked, the semaphore will be unchanged.</P | |
| 179 ></DIV | |
| 180 ><DIV | |
| 181 CLASS="REFSECT1" | |
| 182 ><A | |
|
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183 NAME="AEN7759" |
| 0 | 184 ></A |
| 185 ><H2 | |
| 186 >Examples</H2 | |
| 187 ><P | |
| 188 ><PRE | |
| 189 CLASS="PROGRAMLISTING" | |
| 190 >res = SDL_SemWaitTimeout(my_sem, WAIT_TIMEOUT_MILLISEC); | |
| 191 | |
| 192 if (res == SDL_MUTEX_TIMEOUT) { | |
| 193 return TRY_AGAIN; | |
| 194 } | |
| 195 if (res == -1) { | |
| 196 return WAIT_ERROR; | |
| 197 } | |
| 198 | |
| 199 ... | |
| 200 | |
| 201 SDL_SemPost(my_sem);</PRE | |
| 202 ></P | |
| 203 ></DIV | |
| 204 ><DIV | |
| 205 CLASS="REFSECT1" | |
| 206 ><A | |
|
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207 NAME="AEN7763" |
| 0 | 208 ></A |
| 209 ><H2 | |
| 210 >See Also</H2 | |
| 211 ><P | |
| 212 ><A | |
| 213 HREF="sdlcreatesemaphore.html" | |
| 214 ><TT | |
| 215 CLASS="FUNCTION" | |
| 216 >SDL_CreateSemaphore</TT | |
| 217 ></A | |
| 218 >, | |
| 219 <A | |
| 220 HREF="sdldestroysemaphore.html" | |
| 221 ><TT | |
| 222 CLASS="FUNCTION" | |
| 223 >SDL_DestroySemaphore</TT | |
| 224 ></A | |
| 225 >, | |
| 226 <A | |
| 227 HREF="sdlsemwait.html" | |
| 228 ><TT | |
| 229 CLASS="FUNCTION" | |
| 230 >SDL_SemWait</TT | |
| 231 ></A | |
| 232 >, | |
| 233 <A | |
| 234 HREF="sdlsemtrywait.html" | |
| 235 ><TT | |
| 236 CLASS="FUNCTION" | |
| 237 >SDL_SemTryWait</TT | |
| 238 ></A | |
| 239 >, | |
| 240 <A | |
| 241 HREF="sdlsempost.html" | |
| 242 ><TT | |
| 243 CLASS="FUNCTION" | |
| 244 >SDL_SemPost</TT | |
| 245 ></A | |
| 246 >, | |
| 247 <A | |
| 248 HREF="sdlsemvalue.html" | |
| 249 ><TT | |
| 250 CLASS="FUNCTION" | |
| 251 >SDL_SemValue</TT | |
| 252 ></A | |
| 253 ></P | |
| 254 ></DIV | |
| 255 ><DIV | |
| 256 CLASS="NAVFOOTER" | |
| 257 ><HR | |
| 258 ALIGN="LEFT" | |
| 259 WIDTH="100%"><TABLE | |
| 260 WIDTH="100%" | |
| 261 BORDER="0" | |
| 262 CELLPADDING="0" | |
| 263 CELLSPACING="0" | |
| 264 ><TR | |
| 265 ><TD | |
| 266 WIDTH="33%" | |
| 267 ALIGN="left" | |
| 268 VALIGN="top" | |
| 269 ><A | |
| 270 HREF="sdlsemtrywait.html" | |
| 271 >Prev</A | |
| 272 ></TD | |
| 273 ><TD | |
| 274 WIDTH="34%" | |
| 275 ALIGN="center" | |
| 276 VALIGN="top" | |
| 277 ><A | |
| 278 HREF="index.html" | |
| 279 >Home</A | |
| 280 ></TD | |
| 281 ><TD | |
| 282 WIDTH="33%" | |
| 283 ALIGN="right" | |
| 284 VALIGN="top" | |
| 285 ><A | |
| 286 HREF="sdlsempost.html" | |
| 287 >Next</A | |
| 288 ></TD | |
| 289 ></TR | |
| 290 ><TR | |
| 291 ><TD | |
| 292 WIDTH="33%" | |
| 293 ALIGN="left" | |
| 294 VALIGN="top" | |
| 295 >SDL_SemTryWait</TD | |
| 296 ><TD | |
| 297 WIDTH="34%" | |
| 298 ALIGN="center" | |
| 299 VALIGN="top" | |
| 300 ><A | |
| 301 HREF="thread.html" | |
| 302 >Up</A | |
| 303 ></TD | |
| 304 ><TD | |
| 305 WIDTH="33%" | |
| 306 ALIGN="right" | |
| 307 VALIGN="top" | |
| 308 >SDL_SemPost</TD | |
| 309 ></TR | |
| 310 ></TABLE | |
| 311 ></DIV | |
| 312 ></BODY | |
| 313 ></HTML | |
| 314 > |