Name
NAME
pthread_once — dynamic package initialization
SYNOPSIS
THR #include <pthread.h> int pthread_once (pthread_once_t *once_control
, void (*init_routine
) (void)); pthread_once_tonce_control
= PTHREAD_ONCE_INIT;
DESCRIPTION
The first call to pthread_once() by any thread in a process, with a given once_control, shall call the init_routine with no arguments. Subsequent calls of pthread_once() with the same once_control shall not call the init_routine. On return from pthread_once(), init_routine shall have completed. The once_control parameter shall determine whether the associated initialization routine has been called.
The pthread_once() function is not a cancelation point. However, if init_routine is a cancelation point and is canceled, the effect on once_control shall be as if pthread_once() was never called.
The constant PTHREAD_ONCE_INIT is defined in the <pthread.h> header.
The behavior of pthread_once() is undefined if once_control has automatic storage duration or is not initialized by PTHREAD_ONCE_INIT.
RETURN VALUE
Upon successful completion, pthread_once() shall return zero; otherwise, an error number shall be returned to indicate the error.
ERRORS
The pthread_once() function may fail if:
[EINVAL] | If either once_control or init_routine is invalid. |
The pthread_once() function shall not return an error code of [EINTR].
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
Some C libraries are designed for dynamic initialization. That is, the global initialization for the library is performed ...
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