PTHREAD_ONCE(3C) Standard C Library Functions PTHREAD_ONCE(3C)
NAME
pthread_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(7) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+
SEE ALSO
attributes(7),
standards(7)NOTES
Solaris threads do not offer this functionality.
March 23, 2005 PTHREAD_ONCE(3C)
