Existing implementations vary on the result of a kill() with pid indicating an inactive process (a terminated process that has not been waited for by its parent). Some indicate success on such a call (subject to permission checking), while others give an error of [ESRCH]. Since the definition of process lifetime in this volume of POSIX.1-2008 covers inactive processes, the [ESRCH] error as described is inappropriate in this case. In particular, this means that an application cannot have a parent process check for termination of a particular child with kill(). (Usually this is done with the null signal; this can be done reliably with waitpid().
Regards,
Alister
Historic implementations in 1988 (when the first System Interfaces volume of the POSIX standards was approved) behaved both ways. (Notably UNIX System V succeeded, and 4.3BSD returned an ESRCH error.) The standard required the System V behavior, and that was further reinforced when the 2008 edition of the standard clarified that the lifetime of a process does not end until it is reaped.
But, of course, some implementations of UNIX-like systems do not conform to the standards.
Okay, I'm working within ansi C and Sun Solaris 7. I have a problem with zombies. I'm currently using the kill command to return the status of a process. How do I check for Zombie PIDs or the right function to return its PID from within a C program? (1 Reply)
Hi All
I need help, how can i kill zombies instead of rebooting the system.
Regards
System: sna Tue Apr 5 17:50:23 2005
Load averages: 0.05, 0.15, 0.22
168 processes: 157 sleeping, 5 running, 6 zombies
Cpu states:
CPU LOAD USER NICE... (5 Replies)
i'm writing small http proxy server (accept client -> connect to remote proxy server -> recv client's request -> send to remote proxy server -> get responce from remote proxy server -> send answer to client -> close connection to client and to remote proxy server) and having problems with fork().... (2 Replies)
I had a problem deleting a zombie process. It refused to be killed.
I even tried kill -9 process# but it refused.
Any other way of killing it? (7 Replies)
what are the precautions to be taken care for avoiding zombie process ? (8 Replies)
Discussion started by: Gopi Krishna P
8 Replies
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killpg
KILLPG(3) Linux Programmer's Manual KILLPG(3)NAME
killpg - send signal to a process group
SYNOPSIS
#include <signal.h>
int killpg(int pgrp, int sig);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
killpg():
_XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE
DESCRIPTION
killpg() sends the signal sig to the process group pgrp. See signal(7) for a list of signals.
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 the permissions required to send a signal to another process, see kill(2).
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
ERRORS
EINVAL sig is not a valid signal number.
EPERM The process does not have permission to send the signal to any of the target processes. For the required permissions, see kill(2).
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.
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, SVr4, 4.4BSD (killpg() first appeared in 4BSD).
NOTES
There are various differences between the permission checking in BSD-type systems and System 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 tar-
get processes.
C library/kernel differences
On Linux, killpg() is implemented as a library function that makes the call kill(-pgrp, sig).
SEE ALSO getpgrp(2), kill(2), signal(2), capabilities(7), credentials(7)COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
Linux 2017-09-15 KILLPG(3)