Add a manpage for pthread_atfork(3). This copies a lot of the text of

the Open Group manpage for pthread_atfork(), available online at:

http://www.opengroup.org/onlinepubs/009695399/functions/pthread_atfork.html

which should be ok, since Daniel Eischen had mailed me about Open
Group manpages and the fact that they have granted permission to
FreeBSD to use their material.  Any differences from the OG text are
my changes to the original manpage text submitted by Alex Vasylenko:

- In an effort to clean up the part that describes hooks and their
  calling order, I used a list instead of a single paragraph for all the three
  types of fork() hooks.
- After a short discussion with Dima Dorfman a long long time ago in a
  far away galaxy, I changed the RETURN VALUES section to look more
  like the rest of the pthread_xxx.3 manpages.

PR:		docs/68201
Submitted by:	Alex Vasylenko <lxv@omut.org>

3 files changed, 117 insertions, 0 deletions

diff --git a/share/man/man3/Makefile b/share/man/man3/Makefile
index 6aa8b26..c3b9287 100644
--- a/share/man/man3/Makefile
+++ b/share/man/man3/Makefile
@@ -142,6 +142,7 @@ MLINKS+=	tree.3 RB_EMPTY.3 \
 
 .if !defined(NO_LIBC_R) || !defined(NO_LIBPTHREAD) || !defined(NO_LIBTHR)
 PTHREAD_MAN=	pthread.3 \
+		pthread_atfork.3 \
 		pthread_attr.3 \
 		pthread_attr_get_np.3 \
 		pthread_attr_setcreatesuspend_np.3 \
diff --git a/share/man/man3/pthread.3 b/share/man/man3/pthread.3
index 076aefe..5ebb88d 100644
--- a/share/man/man3/pthread.3
+++ b/share/man/man3/pthread.3
@@ -447,6 +447,15 @@ Set the thread-specific value for the specified key.
 .Ss Cleanup Routines
 .Bl -tag -width indent
 .It Xo
+.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
+.Xc
+Register fork handlers
+.It Xo
 .Ft void
 .Fn pthread_cleanup_pop "int execute"
 .Xc
@@ -472,6 +481,7 @@ They contain both thread-safe versions of
 functions and the thread functions.
 Threaded applications are linked with one of these libraries.
 .Sh SEE ALSO
+.Xr pthread_atfork 3 ,
 .Xr pthread_cleanup_pop 3 ,
 .Xr pthread_cleanup_push 3 ,
 .Xr pthread_condattr_destroy 3 ,
diff --git a/share/man/man3/pthread_atfork.3 b/share/man/man3/pthread_atfork.3
new file mode 100644
index 0000000..fbdf018
--- /dev/null
+++ b/share/man/man3/pthread_atfork.3
@@ -0,0 +1,106 @@
+.\" Copyright (c) 2004 Alex Vasylenko <lxv@omut.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.
+.\"
+.\" $FreeBSD$
+.\"
+.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 .
+.Pp
+The handlers registered with
+.Nm
+are called at the moments in time described below:
+.Bl -tag -width "prepare"
+.It Fa prepare
+Before
+.Xr fork 2
+processing commences in the parent process.
+If more than one
+.Fa prepare
+handler is registered they will be called in the opposite order
+they were registered.
+.It Fa parent
+After
+.Xr fork 2
+completes in the parent process.
+If more than one
+.Fa parent
+handler is registered they will be called in the same order
+they were registered.
+.It Fa child
+After
+.Xr fork 2
+processing completes in the child process.
+If more than one
+.Fa child
+handler is registered they will be called in the same order
+they were registered.
+.El.
+.Pp
+If no handling is desired at one or more of these three points,
+a null pointer may be passed as the corresponding fork handler.
+.Sh RETURN VALUES
+If successful, the
+.Fn pthread_atfork
+function will return zero.
+Otherwise an error number will be 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 .
+.Sh AUTHORS
+This manpage was written by
+.An Alex Vasylenko
+.Aq lxv@omut.org .