dispatch_once(3) Library Functions Manual dispatch_once(3) NAME dispatch_once -- execute a block only once SYNOPSIS #include <dispatch/dispatch.h> void dispatch_once(dispatch_once_t *predicate, void (^block)(void)); void dispatch_once_f(dispatch_once_t *predicate, void *context, void (*function)(void *)); DESCRIPTION The dispatch_once() function provides a simple and efficient mechanism to run an initializer exactly once, similar to pthread_once(3). Well designed code hides the use of lazy initialization. For example: FILE *getlogfile(void) { static dispatch_once_t pred; static FILE *logfile; dispatch_once(&pred, ^{ logfile = fopen(MY_LOG_FILE, "a"); }); return logfile; } FUNDAMENTALS The dispatch_once() function is a wrapper around dispatch_once_f(). SEE ALSO dispatch(3) Darwin May 1, 2009 dispatch_once(3)
NAME | SYNOPSIS | DESCRIPTION | FUNDAMENTALS | SEE ALSO
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