.\"

.\" $FreeBSD: src/share/man/man3/pthread_atfork.3,v 1.0 2004/06/21 15:59:00 xx Exp $

.\"

.Dd June 21, 2004

.Dt PTHREAD_ATFORK 3

.Os

.Sh NAME

.Nm pthread_atfork

.Nd register fork handlers

.Sh LIBRARY

.Lb libpthread

.Sh SYNOPSIS

.In pthread.h

.Ft int

.Fo pthread_atfork

.Fa "void \*[lp]*prepare\*[rp]\*[lp]void\*[rp]"

.Fa "void \*[lp]*parent\*[rp]\*[lp]void\*[rp]"

.Fa "void \*[lp]*child\*[rp]\*[lp]void\*[rp]"

.Fc

.Sh DESCRIPTION

The

.Fn pthread_atfork

function declares fork handlers to be called before and after

.Xr fork 2 ,

in the context of the thread that called

.Xr fork 2 .

The

.Fa prepare

fork handler will be called before

.Xr fork 2

processing commences.

The

.Fa parent

fork handle will be called after

.Xr fork 2

processing completes in the parent process.

The

.Fa child

fork handler will be called after

.Xr fork 2

processing completes in the child process.

If no handling is desired at one or more of these three points, the

corresponding fork handler address(es) may be set to NULL.

.Pp

The order of calls to 

.Fn pthread_atfork

is significant.

The

.Fa parent

and

.Fa child

fork handlers will be called in the order in which they were 

established by calls to

.Fn pthread_atfork .

The

.Fa prepare

fork handlers will be called in the opposite order.

.Sh RETURN VALUES

Upon successful completion,

.Fn pthread_atfork

returns a value of zero; otherwise, an error number is returned

to indicate the error.

.Sh ERRORS

The

.Fn pthread_atfork

function will fail if:

.Bl -tag -width Er

.It Bq Er ENOMEM

Insufficient table space exists to record the fork handler addresses.

.Sh SEE ALSO

.Xr fork 2 ,

.Xr pthread 3

.Sh STANDARDS

The

.Fn pthread_atfork

function is expected to conform to

.St -p1003.1 .