pthread_atfork(3) [mojave man page]

PTHREAD_ATFORK(3)					   BSD Library Functions Manual 					 PTHREAD_ATFORK(3)

NAME

     pthread_atfork -- register handlers to be called before and after fork()

SYNOPSIS

     #include <pthread.h>

     int
     pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void));

DESCRIPTION

     The pthread_atfork() function declares fork handlers to be called before and after fork(2), in the context of the thread that called fork(2).

     The handlers registered with pthread_atfork() are called at the moments in time described below:

     prepare  Before fork(2) processing commences in the parent process.  If more than one prepare handler is registered they will be called in
	      the opposite order they were registered.

     parent   After fork(2) completes in the parent process.  If more than one parent handler is registered they will be called in the same order
	      they were registered.

     child    After fork(2) processing completes in the child process.	If more than one child handler is registered they will be called in the
	      same order they were registered.

     If no handling is desired at one or more of these three points, a null pointer may be passed as the corresponding fork handler.

     Important: only async-signal-safe functions are allowed on the child side of fork().  See sigaction(2) for details.

RETURN VALUES

     If successful, the pthread_atfork() function will return zero.  Otherwise an error number will be returned to indicate the error.

ERRORS

     The pthread_atfork() function will fail if:

     [ENOMEM]		The system lacked the necessary resources to add another handler to the list.

SEE ALSO

     fork(2), pthread(3)

STANDARDS

     The pthread_atfork() conforms to ISO/IEC 9945-1:1996 (``POSIX.1'').

BSD
								   June 21, 2004							       BSD

PTHREAD_ATFORK(3)					     Library Functions Manual						 PTHREAD_ATFORK(3)

NAME

       pthread_atfork - register handlers to be called at fork(2) time

SYNOPSIS

       #include <pthread.h>

       int pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void));

DESCRIPTION

       pthread_atfork registers handler functions to be called just before and just after a new process is created with fork(2).  The prepare han-
       dler will be called from the parent process, just before the new process is created. The parent handler will  be  called  from  the  parent
       process, just before fork(2) returns. The child handler will be called from the child process, just before fork(2) returns.

       One or several of the three handlers prepare, parent and child can be given as NULL, meaning that no handler needs to be called at the cor-
       responding point.

       pthread_atfork can be called several times to install several sets of handlers. At fork(2) time, the prepare handlers are  called  in  LIFO
       order  (last  added  with  pthread_atfork,  first  called before fork), while the parent and child handlers are called in FIFO order (first
       added, first called).

       To understand the purpose of pthread_atfork, recall that fork(2) duplicates the whole memory space,  including  mutexes	in  their  current
       locking	state, but only the calling thread: other threads are not running in the child process.  The mutexes are not usable after the fork
       and must be initialized with pthread_mutex_init in the child process.  This is a limitation of the  current  implementation  and  might	or
       might not be present in future versions.

RETURN VALUE

       pthread_atfork returns 0 on success and a non-zero error code on error.

ERRORS

       ENOMEM insufficient memory available to register the handlers.

AUTHOR

       Xavier Leroy <Xavier.Leroy@inria.fr>

SEE ALSO

       fork(2), pthread_mutex_lock(3), pthread_mutex_unlock(3).

								   LinuxThreads 						 PTHREAD_ATFORK(3)