.\" Copyright (c) 1983, 1991 Regents of the University of California.
+.\" and Copyright (C) 2007, Michael Kerrisk <mtk.manpages@gmail.com>
.\" All rights reserved.
.\"
+.\" %%%LICENSE_START(BSD_4_CLAUSE_UCB)
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 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
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+.\" %%%LICENSE_END
.\"
.\" @(#)getpgrp.2 6.4 (Berkeley) 3/10/91
.\"
.\" Modified 1996-07-21 by Andries Brouwer <aeb@cwi.nl>
.\" Modified 1996-11-06 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 1999-09-02 by Michael Haardt <michael@moria.de>
-.\" Modified 2002-01-18 by Michael Kerrisk <mtk-manpages@gmx.net>
+.\" Modified 2002-01-18 by Michael Kerrisk <mtk.manpages@gmail.com>
.\" Modified 2003-01-20 by Andries Brouwer <aeb@cwi.nl>
.\" 2007-07-25, mtk, fairly substantial rewrites and rearrangements
.\" of text.
.\"
-.TH SETPGID 2 2007-07-26 "Linux" "Linux Programmer's Manual"
+.TH SETPGID 2 2017-09-15 "Linux" "Linux Programmer's Manual"
.SH NAME
setpgid, getpgid, setpgrp, getpgrp \- set/get process group
.SH SYNOPSIS
+.B #include <sys/types.h>
+.br
.B #include <unistd.h>
-.sp
+.PP
.BI "int setpgid(pid_t " pid ", pid_t " pgid );
.br
.BI "pid_t getpgid(pid_t " pid );
-.sp
-.BR "pid_t getpgrp(void);" " /* POSIX.1 version */"
+.PP
+.BR "pid_t getpgrp(void);" " /* POSIX.1 version */"
.br
-.BI "pid_t getpgrp(psid_t " pid ");\ \ \ \ \ \ \ \ \ "
+.BI "pid_t getpgrp(pid_t " pid ");\ \ \ \ \ \ \ \ \ \ \ "
/* BSD version */
-.sp
-.BR "int setpgrp(void);" " /* System V version */"
+.PP
+.BR "int setpgrp(void);" " /* System V version */"
.br
-.BI "int setpgrp(pid_t " pid ", pid_t " pgid );
+.BI "int setpgrp(pid_t " pid ", pid_t " pgid ");\ "
/* BSD version */
-.sp
+.PP
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
-.sp
+.PP
.ad l
.BR getpgid ():
+.RS 4
_XOPEN_SOURCE\ >=\ 500
+.\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
.br
-.BR setpgrp ()
-(POSIX.1): _SVID_SOURCE || _XOPEN_SOURCE >= 500
-.sp
+ || /* Since glibc 2.12: */ _POSIX_C_SOURCE\ >=\ 200809L
+.RE
+.PP
+.BR setpgrp "() (POSIX.1):"
+.nf
+ _XOPEN_SOURCE\ >=\ 500
+.\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
+ || /* Since glibc 2.19: */ _DEFAULT_SOURCE
+ || /* Glibc versions <= 2.19: */ _SVID_SOURCE
+.fi
+.PP
.BR setpgrp "()\ (BSD),"
.BR getpgrp "()\ (BSD):"
-_BSD_SOURCE && !\ (_POSIX_SOURCE || _POSIX_C_SOURCE ||
-_XOPEN_SOURCE || _XOPEN_SOURCE_EXTENDED || _GNU_SOURCE || _SVID_SOURCE)
-.ad b
+.nf
+ [These are available only before glibc 2.19]
+ _BSD_SOURCE &&
+ !\ (_POSIX_SOURCE || _POSIX_C_SOURCE || _XOPEN_SOURCE ||
+ _GNU_SOURCE || _SVID_SOURCE)
+.fi
+.ad
.SH DESCRIPTION
All of these interfaces are available on Linux,
and are used for getting and setting the
for retrieving the calling process's PGID; and
.BR setpgid (),
for setting a process's PGID.
-
+.PP
.BR setpgid ()
sets the PGID of the process specified by
.I pid
.IR pgid .
If
.I pid
-is zero, the process ID of the current process is used.
+is zero, then the process ID of the calling process is used.
If
.I pgid
-is zero, the process ID of the process specified by
+is zero, then the PGID of the process specified by
.I pid
-is used.
+is made the same as its process ID.
If
.BR setpgid ()
is used to move a process from one process
In this case,
the \fIpgid\fP specifies an existing process group to be joined and the
session ID of that group must match the session ID of the joining process.
-
+.PP
The POSIX.1 version of
.BR getpgrp (),
which takes no arguments,
returns the PGID of the calling process.
-
+.PP
.BR getpgid ()
returns the PGID of the process specified by
.IR pid .
If
.I pid
-is zero, the process ID of the current process is used.
+is zero, the process ID of the calling process is used.
(Retrieving the PGID of a process other than the caller is rarely
necessary, and the POSIX.1
.BR getpgrp ()
is preferred for that task.)
-
-The System V-style
+.PP
+The System\ V-style
.BR setpgrp (),
which takes no arguments, is equivalent to
.IR "setpgid(0,\ 0)" .
-
+.PP
The BSD-specific
.BR setpgrp ()
call, which takes arguments
.I pid
and
.IR pgid ,
-is equivalent to
-.IR "setpgid(pid, pgid)" .
+is a wrapper function that calls
+.PP
+ setpgid(pid, pgid)
+.PP
.\" The true BSD setpgrp() system call differs in allowing the PGID
.\" to be set to arbitrary values, rather than being restricted to
.\" PGIDs in the same session.
-
+Since glibc 2.19, the BSD-specific
+.BR setpgrp ()
+function is no longer exposed by
+.IR <unistd.h> ;
+calls should be replaced with the
+.BR setpgid ()
+call shown above.
+.PP
The BSD-specific
.BR getpgrp ()
call, which takes a single
.I pid
-argument, is equivalent to
-.IR "getpgid(pid)" .
-.SH "RETURN VALUE"
+argument, is a wrapper function that calls
+.PP
+ getpgid(pid)
+.PP
+Since glibc 2.19, the BSD-specific
+.BR getpgrp ()
+function is no longer exposed by
+.IR <unistd.h> ;
+calls should be replaced with calls to the POSIX.1
+.BR getpgrp ()
+which takes no arguments (if the intent is to obtain the caller's PGID),
+or with the
+.BR getpgid ()
+call shown above.
+.SH RETURN VALUE
On success,
.BR setpgid ()
and
On error, \-1 is returned, and
.I errno
is set appropriately.
-
+.PP
The POSIX.1
.BR getpgrp ()
always returns the PGID of the caller.
-
+.PP
.BR getpgid (),
and the BSD-specific
.BR getpgrp ()
For
.BR setpgid ():
.I pid
-is not the current process and not a child of the current process.
-.SH "CONFORMING TO"
+is not the calling process and not a child of the calling process.
+.SH CONFORMING TO
.BR setpgid ()
and the version of
.BR getpgrp ()
-with no argumennts
+with no arguments
conform to POSIX.1-2001.
-
+.PP
POSIX.1-2001 also specifies
.BR getpgid ()
and the version of
.BR setpgrp ()
that takes no arguments.
-
+(POSIX.1-2008 marks this
+.BR setpgrp ()
+specification as obsolete.)
+.PP
The version of
.BR getpgrp ()
with one argument and the version of
inherits its parent's process group ID.
The PGID is preserved across an
.BR execve (2).
-
+.PP
Each process group is a member of a session and each process is a
member of the session of which its process group is a member.
-
+(See
+.BR credentials (7).)
+.PP
A session can have a controlling terminal.
At any time, one (and only one) of the process groups
in the session can be the foreground process group
from the terminal;
if a background process group tries to
.BR read (2)
-from the terminal, then the group is send a
-.BR SIGTSTP
+from the terminal, then the group is sent a
+.B SIGTTIN
signal, which suspends it.
The
.BR tcgetpgrp (3)
.BR tcsetpgrp (3)
functions are used to get/set the foreground
process group of the controlling terminal.
-
+.PP
The
.BR setpgid ()
and
calls are used by programs such as
.BR bash (1)
to create process groups in order to implement shell job control.
-
-If a session has a controlling terminal, and the
-.B CLOCAL
-flag for that terminal is not set,
-and a terminal hangup occurs, then the session leader is sent a
-.BR SIGHUP .
-If the session leader exits, then a
-.B SIGHUP
-signal will also be sent to each process in the foreground
-process group of the controlling terminal.
-
-If the exit of the process causes a process group to become orphaned,
+.PP
+If the termination of a process causes a process group to become orphaned,
and if any member of the newly orphaned process group is stopped, then a
.B SIGHUP
signal followed by a
.B SIGCONT
signal will be sent to each process
in the newly orphaned process group.
-.SH "SEE ALSO"
+.\" exit.3 refers to the following text:
+An orphaned process group is one in which the parent of
+every member of process group is either itself also a member
+of the process group or is a member of a process group
+in a different session (see also
+.BR credentials (7)).
+.SH SEE ALSO
.BR getuid (2),
.BR setsid (2),
.BR tcgetpgrp (3),
.BR tcsetpgrp (3),
-.BR termios (3)
+.BR termios (3),
+.BR credentials (7)
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