killpg - send signal to a process group
int killpg(int pgrp, int sig);
Killpg sends the signal sig to the process group pgrp. See sigac-
tion(2) for a list of signals. If pgrp is 0, killpg sends the signal
to the sending process's process group.
The sending process and members of the process group must have the same
effective user ID, or the sender must be the super-user. As a single
special case the continue signal SIGCONT may be sent to any process
that is a descendant of the current process.
On success, zero is returned. On error, -1 is returned, and errno is
EINVAL Sig is not a valid signal number.
ESRCH No process can be found in the process group specified by pgrp.
ESRCH The process group was given as 0 but the sending process does
not have a process group.
EPERM The sending process is not the super-user and one or more of the
target processes has an effective user ID different from that of
the sending process.
SVr4, 4.4BSD (The killpg function call first appeared in 4.0BSD).
kill(2), getpgrp(2), signal(2)
BSD Man Page 1993-07-23 killpg(2)