— get process group
The process group of the current process is returned by
The process group of the pid process is returned by
If pid is zero,
returns the process group of the current process.
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.
These calls are thus used by programs such as
csh(1) to create
process groups in implementing job control. The
calls are used to get/set the process group of the controlling terminal.
getpgrp() always succeeds, however
getpgid() will succeed unless:
- The current process and the process pid are not in the same session.
- There is no process with a process ID equal to pid.
getpgid() functions conform to IEEE
Std 1003.1-2008 (“POSIX.1”).
getpgrp() function call that took a
pid_t pid argument appeared in
4.0BSD. This version, without an argument, is
derived from its usage in System V Release 4, and first appeared in
getpgid() function call is derived
from its usage in System V Release 4, and first appeared in