topic Re: captive perl menu - trap user keystrokes in Operating System - HP-UX

captive perl menu - trap user keystrokes

Rick Garland — Wed, 13 Apr 2005 15:03:22 GMT

Hi all:

Got Perl 5.8.3 on HPUX 11x systems. I have made a type of menu program for the helpdesk personnel. Question, I want this menu to be captive (it is) but I also want to prevent users from breaking out of the menu.

What are the traps? How do I define them?

Many thanks!

Re: captive perl menu - trap user keystrokes

A. Clay Stephenson — Wed, 13 Apr 2005 15:15:52 GMT

Signal handlers (traps) in Perl are done almost exactly the way they are done in C.

#!/usr/bin/perl

my $Flag = 0; # we'll set this guy in a 'trap'

sub inttrap
{
$Flag = 1;
return(-1);
} # inttrap

$SIG{INT} = \&inttrap; # associate a signal with a subroutine

# Now for an extremely simple read statement.

my $s = ;

print "Flag = ${Flag}\n"

Examine the value displayed when you do and don't press the intr key.

Re: captive perl menu - trap user keystrokes

A. Clay Stephenson — Wed, 13 Apr 2005 15:18:51 GMT

I should also mention (since this is probably what you want to do) that it's also very easy to ignore signals.

$SIG{INT} = 'IGNORE';
$SIG{HUP} = 'IGNORE';

Re: captive perl menu - trap user keystrokes

Rick Garland — Wed, 13 Apr 2005 15:23:17 GMT

many thanks!