--- /dev/null
+++ Libc/Libc-498.1.5/pthreads/pthread_atfork.3
@@ -0,0 +1,57 @@
+.\" Copyright (c) 2004 Apple Computer, Inc.
+.\"
+.Dd August 12, 2004
+.Dt PTHREAD_ATFORK 3
+.Os
+.Sh NAME
+.Nm pthread_atfork
+.Nd register handlers to be called before and after
+.Fn fork
+.Sh SYNOPSIS
+.Fd #include <pthread.h>
+.Ft int
+.Fn pthread_atfork "void (*prepare)(void)" "void (*parent)(void)" "void (*child)(void)"
+.Sh DESCRIPTION
+The
+.Fn pthread_atfork
+function is used to register functions to be called before and after
+.Fn fork
+The
+.Fa prepare 
+handler is called before
+.Fn fork ,
+while the
+.Fa parent
+and
+.Fa child
+handlers are called after
+.Fn fork
+in the parent and child process, respectively.
+.Fa prepare
+handlers are called in reverse order of their registration, while
+.Fa parent
+and
+.Fa child
+handlers are called in the order in which they were registered. Any of the handlers may
+be NULL.
+.Pp
+Remember: only async-cancel-safe functions are allowed on the child side of
+.Fn fork
+.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
+.Fn pthread_atfork
+will fail if:
+.Bl -tag -width Er
+.It Bq Er ENOMEM
+The system lacked the necessary resources to add another handler to the list.
+.El
+.Sh SEE ALSO
+.Xr fork 2
+.Sh STANDARDS
+.Fn pthread_atfork
+conforms to
+.St -p1003.1-96 .