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Threads Library Functionspthread_once(3THR)


NAME

 pthread_once - initialize dynamic package

SYNOPSIS

 
cc -mt [ flag... ] file... -lpthread [ -lrt 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 TYPEATTRIBUTE VALUE
MT-LevelMT-Safe

SEE ALSO

 

attributes(5)

NOTES

 

Solaris threads do not offer this functionality.


SunOS 5.9Go To TopLast Changed 2 Jun 1998

 
      
      
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.