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
LEARN ABOUT MOJAVE
kill
KILL(2) BSD System Calls Manual KILL(2)NAME
kill -- send signal to a process
SYNOPSIS
#include <signal.h>
int
kill(pid_t pid, int sig);
DESCRIPTION
The kill() function sends the signal specified by sig to pid, a process or a group of processes. Typically, Sig will be one of the signals
specified in sigaction(2). A value of 0, however, will cause error checking to be performed (with no signal being sent). This can be used
to check the validity of pid.
For a process to have permission to send a signal to a process designated by pid, the real or effective user ID of the receiving process must
match that of the sending process or the user must have appropriate privileges (such as given by a set-user-ID program or the user is the
super-user). A single exception is the signal SIGCONT, which may always be sent to any descendant of the current process.
If pid is greater than zero:
Sig is sent to the process whose ID is equal to pid.
If pid is zero:
Sig is sent to all processes whose group ID is equal to the process group ID of the sender, and for which the process has permission;
this is a variant of killpg(2).
If pid is -1:
If the user has super-user privileges, the signal is sent to all processes excluding system processes and the process sending the
signal. If the user is not the super user, the signal is sent to all processes with the same uid as the user, excluding the process
sending the signal. No error is returned if any process could be signaled.
For compatibility with System V, if the process number is negative but not -1, the signal is sent to all processes whose process group ID is
equal to the absolute value of the process number. This is a variant of killpg(2).
RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.
ERRORS
kill() will fail and no signal will be sent if:
[EINVAL] Sig is not a valid, supported signal number.
[EPERM] The sending process is not the super-user and its effective user id does not match the effective user-id of the receiving
process. When signaling a process group, this error is returned if any members of the group could not be signaled.
[ESRCH] No process or process group can be found corresponding to that specified by pid.
[ESRCH] The process id was given as 0, but the sending process does not have a process group.
SEE ALSO getpgrp(2), getpid(2), killpg(2), sigaction(2)STANDARDS
The kill() function is expected to conform to IEEE Std 1003.1-1988 (``POSIX.1'').
4th Berkeley Distribution April 19, 1994 4th Berkeley Distribution