topic Re: Perl daemon question in Operating System - Linux

Perl daemon question

Josef Forman — Tue, 04 Oct 2005 07:26:59 GMT

Hi,
i wrote small useful (only for me :) perl daemon, but I can't adjust its behaviour for signal HUP. I know i can ignore signal by setting...
$SIG{HUP} = 'IGNORE'
, but I need execute my procedure. If i set...
$SIG{HUP} = \&catch_signal
then the procedure is executed, but then it is finished with...
Interrupted system call at ./x.pl line...

Is there any possibility to "mask" the signal a nd execute my procedure only?

Thanks for any help
PF

Re: Perl daemon question

Muthukumar_5 — Tue, 04 Oct 2005 07:33:36 GMT

You can try as,

sub catch_signal {
print("Got HUP signal!\n");
}

$SIG{HUP} = 'catch_signal'
for ($x = 0; $x < 10; $x++) {
print("$x\n");
sleep 1;
}

hth.

Re: Perl daemon question

Muthukumar_5 — Tue, 04 Oct 2005 07:35:50 GMT

Just put ; after $SIG{HUP} = 'catch_signal' ;)

hth.

Re: Perl daemon question

Muthukumar_5 — Tue, 04 Oct 2005 07:37:48 GMT

My try as,

#!/usr/contrib/bin/perl
sub INT_handler {
print("Don't Interrupt!\n");
}

$SIG{HUP} = 'INT_handler';
for ($x = 0; $x < 10; $x++) {
print("$x\n");
sleep 10;
}

# ./tst.pl &
[1] 26431
# 0

# kill -1 26431
Don't Interrupt!
1

hth

Re: Perl daemon question

Josef Forman — Tue, 04 Oct 2005 08:01:39 GMT

I have ; at the end :)
You can check torso of my script...

Re: Perl daemon question

Muthukumar_5 — Wed, 05 Oct 2005 01:24:11 GMT

Ok. Keep continuing with this flow. Get back if you have any problem.

Note: Post this scripting related in hp-ux so that you will more really faster responses.

hth.

Re: Perl daemon question

Ralph Grothe — Wed, 05 Oct 2005 06:42:59 GMT

Hi Josef,

have you had a look at "perldoc perlipc" yet?

There are plenty of short signal handler sample codes.

Also regard the warning note in perlipc about not re-entrant system libraries.
At least prior to Perl 5.8 signal handlers should implement as little (clean-up) action as possible.

Btw. it's better to stick to your usage of sub refs (i.e. the \& form) than the use of symbolic refs of Muthu
(although if you didn't use strict 'refs', and stayed in the same package scope you probably wouldn't notice a difference).