.\" Copyright (c) 1983, 1991 Regents of the University of California.
.\" All rights reserved.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)getpgrp.2	6.5 (Berkeley) 07/30/92
.\"
.Dd 
.Dt GETPGRP 2
.Os BSD 4.2
.Sh NAME
.Nm getpgrp
.Nd get process group
.Sh SYNOPSIS
.Ft pid_t
.Fn getpgrp "void"
.Sh DESCRIPTION
The process group of the current process is returned by
.Fn getpgrp .
.Pp
Process groups are used for distribution of signals, and
by terminals to arbitrate requests for their input: processes
that have the same process group as the terminal are foreground
and may read, while others will block with a signal if they attempt
to read.
.Pp
This call is thus used by programs such as
.Xr csh 1
to create
process groups
in implementing job control.
The
.Fn tcgetpgrp
and
.Fn tcsetpgrp
calls
are used to get/set the process group of the control terminal.
.Sh SEE ALSO
.Xr setpgid 2 ,
.Xr termios 4
.Sh HISTORY
The
.Nm
function call appeared in
.Bx 4.0 .
.Sh STANDARDS
The
.Fn getpgrp
function conforms to IEEE Std 1003.1-1988
.Pq Dq Tn POSIX .
.Sh COMPATABILITY
This version of
.Fn getpgrp
differs from past Berkeley versions because it does
not take a
.Fa "pid_t pid"
argument.  We regret changing this but were forced to in
order to comply with IEEE Std 1003.1-1988
.Pq Dq Tn POSIX .
The reasons \fIthey\fR gave for changing this are quoted
in the next paragraph.  We wonder why they didn't just
change the name to avoid this incompatability.
.Pp
(Quoted from the POSIX Rationale)
.br
\fI4.3BSD provides a
.Fn getpgrp
function that returns the process group ID for a specified process.
Although this function is used to support job control, all known
job-control shells always specify the calling process with this
function.  Thus, the simpler System V
.Fn getpgrp
suffices, and the added complexity of the 4.3BSD
.Fn getpgrp
has been omitted from POSIX.1.\fP