In the default state as soon as you've read something from STDIN, a loop doing a $sel->can_read() will always say it can read something from STDIN, even if you don't type anything more.
Example:
$sel = IO::Select->new();
$sel->add(\*STDIN);

while(1)
{
    print "waiting to read:\n";
    my @handles = $sel->can_read();
    print "can read\n";

    foreach $h (@handles)
    {
        if($h == \*STDIN)
        {
            my $line = <STDIN>;
            my $finish = do_something_with_line($line);
        }
    }
    if($finish) {last;}
}

[download]
This will at first wait until you type something, and after that scroll with 'waiting to read' 'can read', even if you don't type anything more.
(I've got a sneaky feeling it also 'can read' from STDIN as soon as you output something to STDOUT, as well.)
If you take out the two 'print' lines the code still works as expected however, (i.e. it only calls do_something_with_line when it has a whole line including a newline from STDIN)

C.

In reply to Re: IO::Select question by castaway
in thread IO::Select question by Eradicatore

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