.\"
.\" Copyright (c) 2000 Peter Wemm <peter@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD: head/lib/libc/gen/rfork_thread.3 218385 2011-02-06 23:26:14Z jilles $
.\"
.Dd February 6, 2011
.Dt RFORK_THREAD 3
.Os
.Sh NAME
.Nm rfork_thread
.Nd create a rfork-based process thread
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft pid_t
.Fn rfork_thread "int flags" "void *stack" "int (*func)(void *arg)" "void *arg"
.Sh DESCRIPTION
.Bf -symbolic
The
.Fn rfork_thread
function has been deprecated in favor of
.Xr pthread_create 3 .
.Ef
.Pp
The
.Fn rfork_thread
function
is a helper function for
.Xr rfork 2 .
It arranges for a new process to be created and the child process will
call the specified function with the specified argument, while running on
the supplied stack.
.Pp
Using this function should avoid the need to implement complex stack
swap code.
.Sh RETURN VALUES
Upon successful completion,
.Fn rfork_thread
returns the process ID of the child process to the parent process.
Otherwise, a value of -1 is returned
to the parent process, no child process is created, and the global
variable
.Va errno
is set to indicate the error.
.Pp
The child process context is not aware of a return from the
.Fn rfork_thread
function as it begins executing directly with the supplied function.
.Sh ERRORS
See
.Xr rfork 2
for error return codes.
.Sh SEE ALSO
.Xr fork 2 ,
.Xr intro 2 ,
.Xr minherit 2 ,
.Xr rfork 2 ,
.Xr vfork 2 ,
.Xr pthread_create 3
.Sh HISTORY
The
.Fn rfork_thread
function first appeared in
.Fx 4.3 .