diff -r ffa851df0825 -r 2fb8b9db1c86 symbian-qemu-0.9.1-12/libsdl-trunk/docs/html/sdlsemtrywait.html --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/symbian-qemu-0.9.1-12/libsdl-trunk/docs/html/sdlsemtrywait.html Fri Jul 31 15:01:17 2009 +0100 @@ -0,0 +1,319 @@ +SDL_SemTryWait

SDL Library Documentation
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SDL_SemTryWait

Name

SDL_SemTryWait -- Attempt to lock a semaphore but don't suspend the thread.

Synopsis

#include "SDL.h"
+#include "SDL_thread.h"

int SDL_SemTryWait(SDL_sem *sem);

Description

SDL_SemTryWait is a non-blocking varient of +SDL_SemWait. If the value of the semaphore +pointed to by sem is positive it will atomically +decrement the semaphore value and return 0, otherwise it will return +SDL_MUTEX_TIMEDOUT instead of suspending the thread.

After SDL_SemTryWait is successful, the semaphore +can be released and its count atomically incremented by a successful call to +SDL_SemPost.

Return Value

Returns 0 if the semaphore was successfully locked or +either SDL_MUTEX_TIMEDOUT or -1 +if the thread would have suspended or there was an error, respectivly.

If the semaphore was not successfully locked, the semaphore will be unchanged.

Examples

res = SDL_SemTryWait(my_sem);
+
+if (res == SDL_MUTEX_TIMEDOUT) {
+        return TRY_AGAIN;
+}
+if (res == -1) {
+        return WAIT_ERROR;
+}
+
+...
+
+SDL_SemPost(my_sem);