[ELDK] kill an entire process group

[Giuseppe Modugno]

Dear all,

I'm using ELDK4.1 for arm platform and I'd like to kill a shell 
script with all the child processes the script had launched.

For example, if my script example.sh is:
---
#!/bin/sh
sleep 100
---
I want to kill the processes example.sh and sleep launched by 
example.sh.
The usual kill command kills only example.sh, parent process.

I wrote a small C program killpg that uses kill() function to send 
the same signal to all the child processes, by passing -pid (a 
negative number) to the function.

When I use the NFS development system, my killpg program works well 
and I can kill the parent and all the child processes.

When I copy killpg executable to my target system (based on SELF 
ramdisk), kill() function returns with an error, ESRCH (pid argument 
doesn't correspond to a real pid).

libc libraries are the same in my target and nfs development systems. 
What could cause the different behaviour?

Can someone suggest me a better method to kill parent and all the 
child processes?