Home > Archive > Linux/Unix > June 2002 > Trapping signals





You are viewing an archived Text-only version of the thread. To view this thread in it's original format and/or if you want to reply to this thread please [click here]

Author Trapping signals
Boulware5

2002-06-13, 10:47 pm

I'm practicing trapping Unix signals on my Linux machine and it doesn't work for some reason. You should be able to instruct your process to ignore interrupt signals and/or display a message or command. For instance if I do:

$ trap "echo I won't die" 9
$ man trap #Run any process
^Z
$ ps x
$ kill -9 PID
$ ps x

...And it went away. It was supposed to display 'I wont die' and still stay there until I resetted it by issuing a $ trap 9 command. Same thing happens when I $ trap "" 9 (no command).

Any ideas?
The VMS Kid

2002-06-14, 7:06 am

The "9" signal only traps kills (cannot be caught or ignore). Try another signal. The list of the most common I think is like this:

0 - shell exit for any reason, including end of file
1 - hangup
2 - interrupt (DEL key)
3 - quit (CTRL-\; causes program to produce core dump)
9 - kill (cannot be caught or ignore)
15 - terminate, default signal generated by kill(1)

Hope this helps.
Boulware5

2002-06-14, 11:02 am

I am pretty sure I did and still didn't work. I did signal 15 (the default). You should be able to trap that.
The VMS Kid

2002-06-24, 1:23 pm

Hmmm, I'm not sure. Will have to look at some of the docs and see if I can come up with anything.
Sponsored Links





Free Braindumps | MCSE braindumps software forum

Copyright 2003 - 2009 examnotes.net