NAME
pthread_atfork() — register fork handlers.
SYNOPSIS
#include <pthread.h>
int pthread_atfork(
void (*prepare)(void),
void (*parent)(void),
void (*child)(void)
);
PARAMETERS
- prepare
This function is called before performing the
fork().
- parent
This function is called in the parent process after performing the
fork().
- child
This function is called in the child process after performing the
fork().
DESCRIPTION
The
pthread_atfork()
function allows an application to install fork handlers.
These fork handlers will be called before and after a
fork()
operation.
These handlers will be called in the context of the thread calling
fork().
Similar to the
atexit()
handlers, the application does not need to do anything special for these
fork handlers to be called.
They will be invoked by the system when a
fork()
operation occurs.
The
prepare()
function is called before the
fork()
operation in the parent process.
The
parent()
function is called after the
fork()
operation in the parent process.
The
child()
function is called after the
fork()
operation in the child process.
If a fork handler is not needed in one or
more of these three places,
the appropriate fork handler parameter may be set to
NULL.
A process may install multiple fork handling functions.
The
parent()
and
child()
fork handlers will be called in the order in which they were installed
(i.e.,
First-In, First-Out).
The
prepare()
fork handlers will be called in the opposite order (i.e.,
Last-In, First-Out).
RETURN VALUE
Upon successful completion,
pthread_atfork()
returns zero. Otherwise, an error number is returned to indicate the error
(the
errno
variable is not set).
ERRORS
If any of the following occur, the
pthread_atfork()
function returns the corresponding error number:
- [ENOMEM]
There is insufficient table space to install the fork handlers.
AUTHOR
pthread_atfork()
was derived from the IEEE POSIX P1003.1c standard.
STANDARDS CONFORMANCE
pthread_atfork(): POSIX 1003.1c.
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