Trapping signal from shell script... doesn't seem to work?

[Dan Nelson]

In the last episode (Feb 07), Aitor San Juan said:
> I have written a Bourne shell script. This shell script invokes a
> program written in the C language.
> 
> Below is basically the shell script source code. As you can see, the
> C program is not invoked in the background, but in the foreground, so
> the shell script doesn't finish until the C program has finished.
> 
> I want the shell script to trap TERM or INT signals, so when any of
> these are raised, the shell script will try to send SIGTERM to the
> program "myprog":

Since you didn't background "myprog", the shell can't do anything until
it returns, including signal processing.  See the text at

 http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_11

There's a nice page about trap handling and shells at

  http://www3.cons.org/cracauer/bourneshell.html

, which includes an example that does what you want:

 #! /bin/sh
 pid=
 onint()
 {
     kill $pid
 }

 trap onint SIGINT
 ./hardguy &
 pid=$!
 wait $pid



-- 
	Dan Nelson
	dnelson at allantgroup.com