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  75 >SDL_CreateSemaphore</H1
  76 ><DIV
  77 CLASS="REFNAMEDIV"
  78 ><A
  79 NAME="AEN7936"
  80 ></A
  81 ><H2
  82 >Name</H2
  83 >SDL_CreateSemaphore&nbsp;--&nbsp;Creates a new semaphore and assigns an initial value to it.</DIV
  84 ><DIV
  85 CLASS="REFSYNOPSISDIV"
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  87 NAME="AEN7939"
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  90 >Synopsis</H2
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  98 ><PRE
  99 CLASS="FUNCSYNOPSISINFO"
 100 >#include "SDL.h"
 101 #include "SDL_thread.h"</PRE
 102 ><P
 103 ><CODE
 104 ><CODE
 105 CLASS="FUNCDEF"
 106 >SDL_sem *<B
 107 CLASS="FSFUNC"
 108 >SDL_CreateSemaphore</B
 109 ></CODE
 110 >(Uint32 initial_value);</CODE
 111 ></P
 112 ><P
 113 ></P
 114 ></DIV
 115 ></DIV
 116 ><DIV
 117 CLASS="REFSECT1"
 118 ><A
 119 NAME="AEN7946"
 120 ></A
 121 ><H2
 122 >Description</H2
 123 ><P
 124 ><TT
 125 CLASS="FUNCTION"
 126 >SDL_CreateSemaphore()</TT
 127 > creates a new semaphore and
 128 initializes it with the value <TT
 129 CLASS="PARAMETER"
 130 ><I
 131 >initial_value</I
 132 ></TT
 133 >.
 134 Each locking operation on the semaphore by
 135 <A
 136 HREF="sdlsemwait.html"
 137 >SDL_SemWait</A
 138 >,
 139 <A
 140 HREF="sdlsemtrywait.html"
 141 >SDL_SemTryWait</A
 142 > or
 143 <A
 144 HREF="sdlsemwaittimeout.html"
 145 >SDL_SemWaitTimeout</A
 146 >
 147 will atomically decrement the semaphore value. The locking operation will be blocked
 148 if the semaphore value is not positive (greater than zero). Each unlock operation by
 149 <A
 150 HREF="sdlsempost.html"
 151 >SDL_SemPost</A
 152 >
 153 will atomically increment the semaphore value.</P
 154 ></DIV
 155 ><DIV
 156 CLASS="REFSECT1"
 157 ><A
 158 NAME="AEN7955"
 159 ></A
 160 ><H2
 161 >Return Value</H2
 162 ><P
 163 >Returns a pointer to an initialized semaphore or
 164 <SPAN
 165 CLASS="RETURNVALUE"
 166 >NULL</SPAN
 167 > if there was an error.</P
 168 ></DIV
 169 ><DIV
 170 CLASS="REFSECT1"
 171 ><A
 172 NAME="AEN7959"
 173 ></A
 174 ><H2
 175 >Examples</H2
 176 ><P
 177 ><PRE
 178 CLASS="PROGRAMLISTING"
 179 >SDL_sem *my_sem;
 180
 181 my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE);
 182
 183 if (my_sem == NULL) {
 184         return CREATE_SEM_FAILED;
 185 }</PRE
 186 ></P
 187 ></DIV
 188 ><DIV
 189 CLASS="REFSECT1"
 190 ><A
 191 NAME="AEN7963"
 192 ></A
 193 ><H2
 194 >See Also</H2
 195 ><P
 196 ><A
 197 HREF="sdldestroysemaphore.html"
 198 ><TT
 199 CLASS="FUNCTION"
 200 >SDL_DestroySemaphore</TT
 201 ></A
 202 >,
 203 <A
 204 HREF="sdlsemwait.html"
 205 ><TT
 206 CLASS="FUNCTION"
 207 >SDL_SemWait</TT
 208 ></A
 209 >,
 210 <A
 211 HREF="sdlsemtrywait.html"
 212 ><TT
 213 CLASS="FUNCTION"
 214 >SDL_SemTryWait</TT
 215 ></A
 216 >,
 217 <A
 218 HREF="sdlsemwaittimeout.html"
 219 ><TT
 220 CLASS="FUNCTION"
 221 >SDL_SemWaitTimeout</TT
 222 ></A
 223 >,
 224 <A
 225 HREF="sdlsempost.html"
 226 ><TT
 227 CLASS="FUNCTION"
 228 >SDL_SemPost</TT
 229 ></A
 230 >,
 231 <A
 232 HREF="sdlsemvalue.html"
 233 ><TT
 234 CLASS="FUNCTION"
 235 >SDL_SemValue</TT
 236 ></A
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