BSD 4_4 release

[unix-history] / usr / src / lib / libc / sys / fork.2

diff --git a/usr/src/lib/libc/sys/fork.2 b/usr/src/lib/libc/sys/fork.2
index c7e3761..0c290f6 100644 (file)
--- a/usr/src/lib/libc/sys/fork.2
+++ b/usr/src/lib/libc/sys/fork.2
@@ -1,69 +1,108 @@
-.\" Copyright (c) 1980 Regents of the University of California.
-.\" All rights reserved.  The Berkeley software License Agreement
-.\" specifies the terms and conditions for redistribution.
+.\" Copyright (c) 1980, 1991, 1993
+.\"    The Regents of the University of California.  All rights reserved.

 .\"
 .\"

-.\"    @(#)fork.2      6.4 (Berkeley) 5/22/86
+.\" 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.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"    This product includes software developed by the University of
+.\"    California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.

 .\"
 .\"

-.TH FORK 2 "May 22, 1986"
-.UC
-.SH NAME
-fork \- create a new process
-.SH SYNOPSIS
-.ft B
-pid = fork()
-.br
-int pid;
-.ft R
-.SH DESCRIPTION
-.I Fork
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+.\"
+.\"    @(#)fork.2      8.1 (Berkeley) 6/4/93
+.\"
+.Dd June 4, 1993
+.Dt FORK 2
+.Os BSD 4
+.Sh NAME
+.Nm fork
+.Nd create a new process
+.Sh SYNOPSIS
+.Fd #include <unistd.h>
+.Ft pid_t
+.Fn fork void
+.Sh DESCRIPTION
+.Fn Fork

 causes creation of a new process.
 The new process (child process) is an exact copy of the
 causes creation of a new process.
 The new process (child process) is an exact copy of the

-calling process except for the following:
-.in +5n
-.sp
+calling process (parent process) except for the following:
+.Bl -bullet -offset indent
+.It

 The child process has a unique process ID.
 The child process has a unique process ID.

-.sp
-The child process has a different parent process ID (i.e.,
-the process ID of the parent process).
-.sp
+.It
+The child process has a different parent
+process ID (i.e., the process ID of the parent process).
+.It

 The child process has its own copy of the parent's descriptors.
 These descriptors reference the same underlying objects, so that,
 for instance, file pointers in file objects are shared between
 the child and the parent, so that an
 The child process has its own copy of the parent's descriptors.
 These descriptors reference the same underlying objects, so that,
 for instance, file pointers in file objects are shared between
 the child and the parent, so that an

-.IR lseek (2)
+.Xr lseek 2

 on a descriptor in the child process can affect a subsequent
 on a descriptor in the child process can affect a subsequent

-.I read
+.Xr read

 or
 or

-.I write
+.Xr write

 by the parent.
 This descriptor copying is also used by the shell to
 establish standard input and output for newly created processes
 as well as to set up pipes.
 by the parent.
 This descriptor copying is also used by the shell to
 establish standard input and output for newly created processes
 as well as to set up pipes.

-.sp
-The child processes resource utilizations are set to 0;
-see
-.IR setrlimit (2).
-.SH "RETURN VALUE
-Upon successful completion, \fIfork\fP returns a value
+.It
+The child processes resource utilizations
+are set to 0; see
+.Xr setrlimit 2 .
+.El
+.Sh RETURN VALUES
+Upon successful completion,
+.Fn fork
+returns a value

 of 0 to the child process and returns the process ID of the child
 of 0 to the child process and returns the process ID of the child

-process to the parent process.  Otherwise, a value of \-1 is returned
+process to the parent process.  Otherwise, a value of -1 is returned

 to the parent process, no child process is created, and the global
 to the parent process, no child process is created, and the global

-variable \fIerrno\fP is set to indicate the error.
-.SH ERRORS
-.I Fork
-will fail and no child process will be created if one or more of the
-following are true:
-.TP 15
-[EAGAIN]
+variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Fn Fork
+will fail and no child process will be created if:
+.Bl -tag -width [EAGAIN]
+.It Bq Er EAGAIN

 The system-imposed limit on the total
 number of processes under execution would be exceeded.
 This limit is configuration-dependent.
 The system-imposed limit on the total
 number of processes under execution would be exceeded.
 This limit is configuration-dependent.

-.TP 15
-[EAGAIN]
-The system-imposed limit MAXUPRC (\fI<sys/param.h>) \fRon the total number of
+.It Bq Er EAGAIN
+The system-imposed limit
+.Dv MAXUPRC
+.Pq Aq Pa sys/param.h
+on the total number of

 processes under execution by a single user would be exceeded.
 processes under execution by a single user would be exceeded.

-.TP 15
-[ENOMEM]
+.It Bq Er ENOMEM

 There is insufficient swap space for the new process.
 There is insufficient swap space for the new process.

-.SH "SEE ALSO"
-execve(2), wait(2)
+.El
+.Sh SEE ALSO
+.Xr execve 2 ,
+.Xr wait 2
+.Sh HISTORY
+A
+.Fn fork 2
+function call appeared in
+.At v6 .