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 handler 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 corresponding 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)