killpg - send signal to a process group
int killpg(int pgrp, int sig);
Killpg sends the signal sig to the process group pgrp.
See sigaction(2) for a list of signals. If pgrp is 0,
killpg sends the signal to the sending process's process
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 set appropriately.
EINVAL Sig is not a valid signal number.
ESRCH No process can be found in the process group speci
fied 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
kill(2), getpgrp(2), signal(2)