PTHREAD_ONCE(3C)PTHREAD_ONCE(3C)NAMEpthread_once - initialize dynamic package
SYNOPSIS
cc -mt [ flag... ] file... -lpthread [ library... ]
#include <pthread.h>
pthread_once_t once_control = PTHREAD_ONCE_INIT;
int pthread_once(pthread_once_t *once_control,
void (*init_routine)(void));
DESCRIPTION
If any thread in a process with a once_control parameter makes a call
to pthread_once(), the first call will summon the init_routine(), but
subsequent calls will not. The once_control parameter determines
whether the associated initialization routine has been called. The
init_routine() is complete upon return of pthread_once().
pthread_once() is not a cancellation point; however, if the function
init_routine() is a cancellation point and is canceled, the effect on
once_control is the same as if pthread_once() had never been called.
The constant PTHREAD_ONCE_INIT is defined in the <pthread.h> header.
If once_control has automatic storage duration or is not initialized by
PTHREAD_ONCE_INIT, the behavior of pthread_once() is undefined.
RETURN VALUES
Upon successful completion, pthread_once() returns 0. Otherwise, an
error number is returned to indicate the error.
ERRORS
EINVAL
once_control or init_routine is NULL.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Standard │
├────────────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└────────────────────┴─────────────────┘
SEE ALSOattributes(5), standards(5)NOTES
Solaris threads do not offer this functionality.
Mar 23, 2005 PTHREAD_ONCE(3C)
