Find out whether a process is alive

clalfa · 07-18-2007, 04:30 AM

Hi all,
I need to find out whether a process is alive or it is killed (or zombie), and I would like to know if there is a C function which I could call to get this information. Note that the process I need to check is not a child process of the one which has to "investigate".

Do you know if such a function exists?

Thank you in advance

munna_dude · 07-18-2007, 04:45 AM

Quote:

Originally Posted by clalfa

Hi all,
I need to find out whether a process is alive or it is killed (or zombie), and I would like to know if there is a C function which I could call to get this information. Note that the process I need to check is not a child process of the one which has to "investigate".

Do you know if such a function exists?

Thank you in advance

hi
this may be helpfull to you

Quote:

ps -A
or
ps -A | grep "processname"
or
ps -fe | grep "processname"

cheers
munna

clalfa · 07-18-2007, 04:52 AM

The problem is that ps is a shell command...
I need a function which I could call in a C program. Basically, I have the pid of a process and would like to pass that value to a function and get back "alive" or "error" or something like that.
I think I could use a non-blocking waitpid, but that only works if the process you want to find out about is a child of the calling process...

bigearsbilly · 07-18-2007, 05:41 AM

kill -0 pid works in shell

so maybe using sigsend too?

clalfa · 07-18-2007, 06:13 AM

THANK YOU!!!! that's what I was looking for!!

Code:

if ( sigsend (P_PID, n1_id, 0) == 0 )
    printf ("Process %d is alive!!\n", n1_id);

I think this should work...if only the linker could find sigsend!!!

This is what it says:

Code:

:main.c:(.text+0x2ed): undefined reference to `sigsend'

I wonder if I have to include some linking options when launching gcc
(as I do with curses.h: -lncurses). If this helps you, I am using Ubuntu 6.06.1 ....

Please help me!! This is quite an urgent thing...

munna_dude · 07-18-2007, 06:23 AM

Quote:

Originally Posted by clalfa

THANK YOU!!!! that's what I was looking for!!

Code:

if ( sigsend (P_PID, n1_id, 0) == 0 )
    printf ("Process %d is alive!!\n", n1_id);

I think this should work...if only the linker could find sigsend!!!

This is what it says:

Code:

:main.c:(.text+0x2ed): undefined reference to `sigsend'

I wonder if I have to include some linking options when launching gcc
(as I do with curses.h: -lncurses). If this helps you, I am using Ubuntu 6.06.1 ....

Please help me!! This is quite an urgent thing...

mab be it is helpful
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sysexits.h>

cheers
munna

bigearsbilly · 07-18-2007, 07:32 AM

#include <signal.h>

clalfa · 07-18-2007, 08:02 AM

I had already included signal.h, but it doesn't work. That's the strange thing: even if signal.h exists and is in the proper place, it seems that the linker can't find it.
The problem remains, but at least I've found another way of doing what I had to do...

Thank you anyhow for your interest

jiml8 · 07-18-2007, 10:36 AM

Quote:

Originally Posted by clalfa

I had already included signal.h, but it doesn't work. That's the strange thing: even if signal.h exists and is in the proper place, it seems that the linker can't find it.
The problem remains, but at least I've found another way of doing what I had to do...

Thank you anyhow for your interest

and that other way is...