redhat man page for pthread_once

PTHREAD_ONCE(3) 					     Library Functions Manual						   PTHREAD_ONCE(3)

NAME
       pthread_once - once-only initialization

SYNOPSIS
       #include <pthread.h>

       pthread_once_t once_control = PTHREAD_ONCE_INIT;

       int pthread_once(pthread_once_t *once_control, void (*init_routine) (void));

DESCRIPTION
       The  purpose of pthread_once is to ensure that a piece of initialization code is executed at most once. The once_control argument points to
       a static or extern variable statically initialized to PTHREAD_ONCE_INIT.

       The first time pthread_once is called with a given once_control argument, it calls init_routine with no argument and changes the  value	of
       the  once_control  variable  to	record that initialization has been performed. Subsequent calls to pthread_once with the same once_control
       argument do nothing.

RETURN VALUE
       pthread_once always returns 0.

ERRORS
       None.

AUTHOR
       Xavier Leroy <Xavier.Leroy@inria.fr>

								   LinuxThreads 						   PTHREAD_ONCE(3)