getpgrp - get process group
The process group of the current process is returned by
process group of the pid process is returned by getpgid().
Process groups are used for distribution of signals, and by
arbitrate requests for their input: processes that have the
group as the terminal are foreground and may read, while
block with a signal if they attempt to read.
This call is thus used by programs such as csh(1) to create
groups in implementing job control. The tcgetpgrp() and
calls are used to get/set the process group of the control
getpgrp() always succeeds, however getpgid() will succeed
[EPERM] The current process and the process pid are
not in the same
[ESRCH] There is no process with a process ID equal to
This version of getpgrp() differs from past Berkeley versions by not taking
a pid_t pid argument. This incompatibility is required
by IEEE Std
From the IEEE Std 1003.1-1988 (``POSIX'') Rationale:
4.3BSD provides a getpgrp() function that returns the process group ID
for a specified process. Although this function is used to
control, all known job-control shells always specify the
with this function. Thus, the simpler System V getpgrp()
the added complexity of the 4.3BSD getpgrp() has been omitted from
The getpgrp() function conforms to IEEE Std 1003.1-1988
getpgid() function call is derived from its usage in System
V Release 4,
and first appeared in NetBSD 1.2A.
The getpgrp() function call appeared in 4.0BSD.
OpenBSD 3.6 June 4, 1993
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