mirror of https://github.com/GnoConsortium/gno.git
113 lines
3.7 KiB
Groff
113 lines
3.7 KiB
Groff
.\" Copyright (c) 1983, 1991, 1993
|
|
.\" The Regents of the University of California. 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.
|
|
.\" 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.
|
|
.\"
|
|
.\" 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.
|
|
.\"
|
|
.\" @(#)getpgrp.2 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.TH GETPGRP 2 "16 January 1997" GNO "System Calls"
|
|
.SH NAME
|
|
.BR getpgrp
|
|
\- get process group
|
|
.SH SYNOPSIS
|
|
.br
|
|
#include <unistd.h>
|
|
.sp 1
|
|
pid_t
|
|
\fB_getpgrp\fR (pid_t \fIpid\fR);
|
|
.br
|
|
pid_t
|
|
\fBgetpgrp\fR (void);
|
|
.SH DESCRIPTION
|
|
.BR getpgrp
|
|
returns the process group of the current process.
|
|
.BR _getpgrp
|
|
returns the process group of the process specified by
|
|
.IR pid .
|
|
.LP
|
|
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.
|
|
.LP
|
|
This call is thus used by programs such as
|
|
.BR csh (1)
|
|
to create
|
|
process groups
|
|
in implementing job control.
|
|
The
|
|
.BR tcgetpgrp
|
|
and
|
|
.BR tcsetpgrp
|
|
calls
|
|
are used to get/set the process group of the control terminal.
|
|
.SH RETURNS
|
|
On success, the requested process group is returned. On failure, -1 is
|
|
returned and
|
|
.BR errno
|
|
is set.
|
|
.SH STANDARDS
|
|
The
|
|
.BR getpgrp
|
|
function conforms to IEEE Std 1003.1-1988 (POSIX).
|
|
.SH COMPATIBILITY
|
|
This version of
|
|
.BR getpgrp
|
|
differs from past GNO (pre-v2.0.6) and Berkeley versions by not taking a
|
|
.I "pid_t pid"
|
|
argument.
|
|
This incompatibility is required by
|
|
POSIX 1003.1-88.
|
|
.IP "From the POSIX 1003.1-88 Rationale:"
|
|
4.3BSD provides a
|
|
.BR 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
|
|
.BR getpgrp
|
|
suffices, and the added complexity of the 4.3BSD
|
|
.BR getpgrp
|
|
has been omitted from POSIX.1.
|
|
.LP
|
|
The older version of
|
|
.BR getpgrp
|
|
which takes an argument is available as the non-standard function
|
|
.BR _getpgrp .
|
|
.SH SEE ALSO
|
|
.BR job_control (2),
|
|
.BR setpgid (2),
|
|
.BR termios (4)
|
|
.SH HISTORY
|
|
The
|
|
.BR getpgrp
|
|
function call appeared in 4.0BSD.
|