Mercurial > sdl-ios-xcode
view docs/man3/SDL_SemTryWait.3 @ 3191:91b335df6fc8
Fixed bug #750
Since many different event structures include windowID it should be placed near
the beginning of the structure (preferably right after type) so it's position
is the same between different events.
This is to avoid code like this:
if (event.type == SDL_WINDOWEVENT)
win = event.window.windowID;
else if ((SDL_EVENTMASK(event.type) & SDL_KEYEVENTMASK) != 0)
win = event.key.windowID;
else if (event.type == SDL_TEXTINPUT)
win = event.text.windowID;
else if (event.type == SDL_MOUSEMOTION)
win = event.motion.windowID;
else if ((SDL_EVENTMASK(event.type) & (SDL_MOUBUTTONDOWNMASK |
SDL_MOUBUTTONUPMASK)) != 0)
win = event.button.windowID;
else if (event.type == SDL_MOUSEWHEEL)
win = event.wheel.windowID;
...
in favor of:
win = event.window.windowID;
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Wed, 10 Jun 2009 14:00:21 +0000 |
| parents | 546f7c1eb755 |
| children | 1238da4a7112 |
line wrap: on
line source
.TH "SDL_SemTryWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_SemTryWait \- Attempt to lock a semaphore but don\&'t suspend the thread\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" #include "SDL_thread\&.h" .sp \fBint \fBSDL_SemTryWait\fP\fR(\fBSDL_sem *sem\fR); .SH "DESCRIPTION" .PP \fBSDL_SemTryWait\fP is a non-blocking varient of \fI\fBSDL_SemWait\fP\fR\&. If the value of the semaphore pointed to by \fBsem\fR is positive it will atomically decrement the semaphore value and return 0, otherwise it will return \fBSDL_MUTEX_TIMEOUT\fR instead of suspending the thread\&. .PP After \fBSDL_SemTryWait\fP is successful, the semaphore can be released and its count atomically incremented by a successful call to \fISDL_SemPost\fR\&. .SH "RETURN VALUE" .PP Returns \fB0\fR if the semaphore was successfully locked or either \fBSDL_MUTEX_TIMEOUT\fR or \fB-1\fR if the thread would have suspended or there was an error, respectivly\&. .PP If the semaphore was not successfully locked, the semaphore will be unchanged\&. .SH "EXAMPLES" .PP .PP .nf \f(CWres = SDL_SemTryWait(my_sem); if (res == SDL_MUTEX_TIMEOUT) { return TRY_AGAIN; } if (res == -1) { return WAIT_ERROR; } \&.\&.\&. SDL_SemPost(my_sem);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemPost\fP\fR, \fI\fBSDL_SemValue\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00