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.