01-12-2010
you've answered 50% of it, if a parent is forked, then fork is called again, will both the parent and the child be forked or only the child, in other words will both of them be forking in parallel?
fork()
PID1 -> PID2
then fork() again
PID1->PID3
PID2->PID4
?
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LEARN ABOUT MOJAVE
pthread_atfork
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