KILLPG(2) Linux Programmer's Manual KILLPG(2)
killpg - send signal to a process group
int killpg(int pgrp, int sig);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
killpg() sends the signal sig to the process group pgrp. See signal(7) for a list of sig-
If pgrp is 0, killpg() sends the signal to the calling process's process group. (POSIX
says: If pgrp is less than or equal to 1, the behavior is undefined.)
For a process to have permission to send a signal it must either be privileged (under
Linux: have the CAP_KILL capability), or the real or effective user ID of the sending
process must equal the real or saved set-user-ID of the target process. In the case of
SIGCONT it suffices when the sending and receiving processes belong to the same session.
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
EINVAL sig is not a valid signal number.
EPERM The process does not have permission to send the signal to any of the target pro-
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
SVr4, 4.4BSD (the killpg() function call first appeared in 4BSD), POSIX.1-2001.
There are various differences between the permission checking in BSD-type systems and Sys-
tem V-type systems. See the POSIX rationale for kill(). A difference not mentioned by
POSIX concerns the return value EPERM: BSD documents that no signal is sent and EPERM
returned when the permission check failed for at least one target process, while POSIX
documents EPERM only when the permission check failed for all target processes.
On Linux, killpg() is implemented as a library function that makes the call
getpgrp(2), kill(2), signal(2), capabilities(7), credentials(7)
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Linux 2010-09-20 KILLPG(2)