usr/src/lib/libc/sys/getpgrp.2

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.\"     @(#)getpgrp.2   6.4 (Berkeley) 3/10/91
.\"
.Dd March 10, 1991
.Dt GETPGRP 2
.Os BSD 4.2
.Sh NAME
.Nm getpgrp
.Nd get process group
.Sh SYNOPSIS
.Ft pid_t
.Fn getpgrp "int pid"
.Sh DESCRIPTION
The process group of the specified process is returned by
.Fn getpgrp .
If
.Fa pid
is zero, the call applies to the current process.
.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
.Dv TIOCGPGRP
and
.Dv TIOCSPGRP
calls
described in
.Xr termios 4
are used to get/set the process group of the control terminal.
.Sh SEE ALSO
.Xr setpgrp 2 ,
.Xr getuid 2 ,
.Xr termios 4
.Sh HISTORY
The
.Nm
function call appeared in
.Bx 4.0 .