Your code appears to work here (ubuntu linux, perl 5.8.8).

This is using backticks (not a system call, as you have in your code. All I did was to replace the extApp $_ with sleep 5.

Can you give some info on your platform and perl version please, and also let us know what the following script prints on your system? 

#!/usr/bin/perl
use strict;
use warnings;

my @result;
$SIG{ALRM} = sub {
    print "ALARM fired\n";
    die "timeout";
};

eval {
    alarm(3);
    @result = `sleep 5`;
    alarm(0);
};

print "Running after alarm: $@\n";

if ($@) {
    if ($@ =~ /timeout/i) {
      push @result, "App has hanged itself\n";
    } else {
        alarm(0);           # clear the still-pending alarm
        die;                # propagate unexpected exception
    } 
} 

print "result is: ", join('', @result), "\n";

[download]
I get: 
ALARM fired
Running after alarm: timeout at tt.pl line 8.

result is: App has hanged itself

[download]
On a side note, when you propagate the 'die' error, it's best to re-throw the original die object/text with die $@ to give higher-level code a chance of working out what went wrong.

In reply to Re: Backticks and SIGALRM by jbert
in thread Backticks and SIGALRM by nemo

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