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 argu-
ment, it calls init_routine with no argument and changes the value of
the once_control variable to record that initialization has been per-
formed. Subsequent calls to pthread_once with the same once_control ar-
gument do nothing.
RETURN VALUE
pthread_once always returns 0.
ERRORS
None.
Linux man-pages 6.9.1 2024-05-02 pthread_once(3)
Generated by dwww version 1.16 on Tue Dec 16 04:28:08 CET 2025.