Question

I’m writing a script to assist people who’ll scan a barcode and get a response to keep or dispose the scanned sample. I want to have a message, similar to tk’s messagebox or Win32::MsgBox but one that requires no user interaction to go away after three seconds.

Answer 1

My thought was to create the messages in a child process, using alarm to kill the process after a delay. In Tk:

sub tmpMsgBox {
    my ($message,$delay) = @_;
    if (fork() == 0) {
        my $topWin = MainWindow->new;
        my $label = $topWin->Label();
        my $ok = $topWin->Button();
        $label->pack(-side => 'top');
        $ok->pack(-side => 'bottom');
        $label->configure(-text => $message);
        $ok->configure(-text => 'Ok', -command => sub {exit});

        $SIG{ALRM} = sub {exit};
        alarm $delay || 1;
        $topWin->MainLoop;
    }
}

for (3..10) {
    tmpMsgBox("This window will disappear in $_ seconds", $_);
}

I don’t think Tk plays nicely with fork, though, so this idea probably won’t work so well if you are also using Tk in your main process.