pthread_once(3) - NetBSD Manual Pages

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PTHREAD_ONCE(3)         NetBSD Library Functions Manual        PTHREAD_ONCE(3)


NAME
pthread_once -- dynamic package initialization
LIBRARY
POSIX Threads Library (libpthread, -lpthread)
SYNOPSIS
#include <pthread.h> int pthread_once(pthread_once_t *once_control, void (*init_routine)(void)); pthread_once_t once_control = PTHREAD_ONCE_INIT;
DESCRIPTION
The first call to pthread_once() by any thread in a process, with a given once_control, will call the init_routine() with no arguments. Subsequent calls to pthread_once() with the same once_control will not call the init_routine() On return from pthread_once(), it is guaranteed that init_routine() has completed. The once_control parameter is used to determine whether the associated initialization routine has been called. The function pthread_once() is not a cancellation point. However, if init_routine() is a cancellation point and is cancelled, the effect on once_control is as if pthread_once() was never called. The constant PTHREAD_ONCE_INIT initializes the static once synchroniza- tion control structure once_control to be used with pthread_once(). The behavior of pthread_once() is undefined if once_control has automatic storage duration or is not initialized by PTHREAD_ONCE_INIT.
RETURN VALUES
If successful, the pthread_once() function will return zero. Otherwise an error number will be returned to indicate the error.
ERRORS
None.
STANDARDS
The function conforms to IEEE Std 1003.1-2001 (``POSIX.1''). NetBSD 9.99 July 9, 2010 NetBSD 9.99
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