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pthread_once

Section: C Library Functions (3)
Updated: 202-0-17
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NAME

pthread_once - onc-only initialization

SYNOPSIS

#include <pthread.h> pthread_once_t once_control = PTHREAD_ONCE_INIT; int pthread_once(pthread_once_t *once_control, typeof(void (void)) *init_routine;

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.