killpg

Synopsis

#include <signal.h>

int killpg(pid_t pgrp, int sig);

Status

Implemented

Conformance

IEEE Std 1003.1-2017

Description

The killpg() function shall send the signal specified by sig to the process group specified by pgrp.

If pgrp is greater than 1, killpg(pgrp, sig) shall be equivalent to kill(-pgrp, sig). If pgrp is less than or equal to 1, the behavior of killpg() is undefined.

If pgrp is 0, the signal is sent to the process group of the calling process. If pgrp is negative, killpg() fails with EINVAL. If pgrp is 1, the call is equivalent to kill(-1, sig), which sends the signal to all processes in the session of the calling process, so process group 1 cannot be signalled by killpg().

Return value

Upon successful completion, 0 shall be returned. Otherwise, -1 shall be returned and errno set to indicate the error.

Errors

The killpg() function shall fail if:

• EINVAL - The value of the sig argument is an invalid or unsupported signal number.

• EPERM - The process does not have permission to send the signal to any receiving process.

• ESRCH - No process or process group can be found corresponding to that specified by pgrp.

POSIX deviations

The default actions of the job control signals are not implemented: SIGSTOP, SIGTSTP, SIGTTIN and SIGTTOU do not stop the processes of the group and SIGCONT does not continue them (see the deviations of kill()).

Permission to send a signal is not verified. Phoenix-RTOS does not keep user and group IDs of processes, so every process is privileged to send a signal to any other user process and killpg() does not fail with EPERM due to the user IDs of the sending and receiving processes (see the deviations of kill()).