use strict;
use warnings;

use POSIX ();

my $new_interrupt_char = 'A';
my $seconds_to_sleep   = 5;

if ( POSIX::isatty( POSIX::STDIN_FILENO ) ) {

    my $term = POSIX::Termios->new();
    $term->getattr( POSIX::STDIN_FILENO );
    my $old_interrupt_char = $term->getcc( POSIX::VINTR );
    $term->setcc( POSIX::VINTR, ord $new_interrupt_char );
    $term->setattr( POSIX::STDIN_FILENO );
    END {
        # restore the interrupt char to default (Control-C)
        if ( defined $term ) {
            $term->setcc( POSIX::VINTR, $old_interrupt_char );
            $term->setattr( POSIX::STDIN_FILENO );
        }
    }
}

$SIG{INT} = sub {
    print "SIGINT handler called\n";
};

my $slept = sleep $seconds_to_sleep;   # use waitpid instead of sleep
if ( $slept != $seconds_to_sleep and $! == POSIX::EINTR ) {
    print "Sleep was interrupted, slept $slept secs\n";
}