I've found that under Windows 98 there seems to be a limit on the number of opens from a pipe that can be done. What I had was 
use warnings;

$runcount = 0;

while(1) {

    # see if there is an internet connection running

    open(IPCONFIG,"ipconfig|") || fatal("Can't fork ipconfig");
    $runcount++;
    print "Good opens so far $runcount\n";
    while(<IPCONFIG>) {
        if (/IP Address/) {
            ($ipaddr) = /(\d+.\d+.\d+.\d+)/;
            last;
        }
    }
    close(IPCONFIG);
    
    sleep 1;
}

sub fatal {
    my ($rpt) = @_;
    print STDERR "Fatal Error Report\n\n";
    print STDERR "Reason $rpt\n";
    print STDERR "Error $^E\n";
    print STDERR "Good opens $runcount\n";
    die;
}

[download]

This fails after 64 opens (a mystical number! but very small for these inflationary times). It was suggested to me that W98 fakes pipes by writing to a temporary file and then making the temporary file available for input. So I though the way round it was to make the command output available through backticks thusly
    $res = `IPCONFIG`;
    fatal("Call failed") if (!defined $res);    
    $runcount++;
    ($ipaddr) = ($res =~ /(\d+.\d+.\d+.\d+)/);

[download]

but this also fails on the 65th attempt. It looks as though backticks are faked also.

Two questions
1) does anyone know of a way around this and
2) can anyone confirm that W2000 doesn't suffer from this problem (I'm pretty sure that NT 5 doesn't but I'll have to wait until I'm back in work to try it)

Thanks in anticipation of another interesting thread.

Odud

In reply to Win98 strangeness by Odud

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