mbrouillet has asked for the wisdom of the Perl Monks concerning the following question:

Hello, When I run this script, 
#!/usr/bin/perl
use Term::ReadLine;
 
use sigtrap 'handler' => \&myhand, 'INT';
sub myhand
{
  print "\n caught $SIG{INT}",@_,"\n";
}

my $term = Term::ReadLine->new('test');
print $term->ReadLine()."\n";
$term->readline("try CTRL-C in some text here :");

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I get a «^C» character displayed when I hit CTRL-C, but the signal is only processed once I type the Enter key. Here is the output : 
marcel@machine:/tmp$ perl test.pl 
Term::ReadLine::Gnu
try CTRL-C in some text here :auie ^C

 caught CODE(0x558c9e99acb0)INT
marcel@machine:/tmp$

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How can I catch it sooner ? Thanks.

Note : I use $term->AddDefun() and $term->bind_keyseq() to catch CTRL-UP/DOWN successfully, but this appears to be limited to some keys. I can't bind to CTRL-Enter for instance as I don't get a key-sequence as I do for CTRL-UP. Is this all related ?

Replies are listed 'Best First'.
Re: Catching INT in Term::ReadLine::Gnu->readline()
by hippo (Archbishop) on Jul 03, 2019 at 11:00 UTC

    Your code as supplied works for me in that it produces the output which I believe you were expecting:

    $ perl cctrap.pl 
Term::ReadLine::Stub
try CTRL-C in some text here :abcd^C
 caught CODE(0x194e9a0)INT
xyz
$

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    The input sequence is: abcd^Cxyz<RETURN>

    This runs with perl v5.20.3 and Term::ReadLine 1.14 from bash on Linux. Maybe you just need to avoid Term::ReadLine::Gnu?

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Re: Catching INT in Term::ReadLine::Gnu->readline()
by gnosti (Chaplain) on Jul 03, 2019 at 18:45 UTC
    Hi,

    I use Terminal::ReadLine::Gnu with the AnyEvent asynchronous framework in an application and manage to immediately catch Ctrl-C.

    Edit

    I am replacing previous code with a working example 

    use Term::ReadLine;
use AnyEvent;
use Event;
use strict;
use warnings;

my $events = {};
my $text = {};
my $term = Term::ReadLine->new("MyApp");
($text->{screen_lines}, $text->{screen_columns}) = $term->get_screen_s
+ize();

# create a STDIN watcher 

$events->{stdin} = AE::io(*STDIN, 0, sub {
    &{$term->Attribs->{'callback_read_char'}}();
});

$term->callback_handler_install(prompt(), \&process_line);

# handle Control-C from terminal

$events->{sigint} = AE::signal('INT', \&cleanup_exit); 

$term->stuff_char(10); # necessary to respond to Ctrl-C at first promp
+t 
&{$term->Attribs->{'callback_read_char'}}();
print prompt();

$Event::DIED = sub 
{
    my ($event, $errmsg) = @_;
    print($errmsg);
    $term->Attribs->{line_buffer} = q();
    if($term){
        $term->clear_message();
        $term->rl_reset_line_state();
    }
};
Event::loop();

sub cleanup_exit
{
  print "\n caught $SIG{INT}",@_,"\n";
  $term->rl_deprep_terminal();
  exit;
}

sub prompt {"Enter command : "}


sub process_line 
{  
    my ($input) = @_; 
    print "got some text: $input\n";
}

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