Re: Perl Term::ReadLine::Gnu Signal Handling Difficulties

[Mr. Muskrat]

You access GNU Readline variables through the Attribs method (with the rl_ stripped). Term::ReadLine::Gnu_Variables

#!/usr/bin/perl
use strict;
use warnings;
use Term::ReadLine;

$SIG{TERM} = sub { print "I got a TERM\n"; exit; };
$SIG{INT} = sub { print "I got a INT\n"; exit; };
# add any additional signal handlers you want

my $term = Term::ReadLine->new('Term1');
$term->ornaments(0);
my $attribs = $term->Attribs;
$attribs->{catch_signals} = 0; # the default is 1
my $prompt = 'cmd> ';
while ( defined (my $cmd = $term->readline($prompt)) ) {
    chomp($cmd);
    if ($cmd =~ /^help$/) {
        print "Help Menu\n";
    }
    else {
        print "Nothing\n";
    }
}

Update: Added $SIG{INT}

[sgt_b2002]

Hi Mr. Muskrat

Thanks for the help. I tried the script you provided and can see how to set the Gnu variables now, but my script still doesn't act how I think it should.

Given the script you provided, I'll hit control-c to send an INT to the script while at the prompt. I expect to see "I got a INT" right after I hit control-c. Instead, the script stays at the prompt until I hit enter. After hitting enter I see "I got a INT".

Is this the designed behavior? Ideally, I'd like to have the signal handlers trigger as soon as the signal is received.

Thanks again for helping me out. :)

[Mr. Muskrat]

It works for me; that is to say that when I run it and press ctrl-c, it exits with "I got a INT".

We are going to need more information about the environment where you are testing this. Let's start with operating system, version of Perl, version of Term::ReadLine::Gnu and version of GNU Readline library version should be sufficient for now.

By the way, it's impolite to cross-post without saying you've cross-posted. http://stackoverflow.com/questions/13316232/perl-termreadlinegnu-signal-handling-difficulties

[sgt_b2002]

Thanks again for the reply. I'll be sure to mention cross positing if it happens again as well.

So I've tested this in two environments and in each, the ctrl-c isn't handled until I press enter. Here are the two environments.

OS: Gentoo Linux 2.6.35 x86_64
Perl: 5.12.4
Term::ReadLine::Gnu: 1.20
readline version: 6.2_p1

OS: Gentoo Linux 3.3.8 x86_64
Perl: 5.16.1
Term::ReadLine::Gnu: 1.20
readline version: 6.2_p1

As an aside, I added the following line as a quick check to make sure I'm using Term::ReadLine::Gnu when testing this on different machines.

print $term->ReadLine."\n";

Again, thanks for your help with this. :)