#!/usr/bin/perl -w
use strict;
use feature ':5.10';

{ no warnings "all";
  $SIG{__WARN__} = sub { };    #pretend "no warnings" works
  require "sys/ioctl.ph";
}

sub getwinsize (;$) {
  my $recheck=$_[0];
  my $winsize=0;
  state ($maxcols, $maxrows);

  return ($maxcols,$maxrows) if $maxcols && $maxrows && !$recheck;

  my $err = ioctl STDOUT, &TIOCGWINSZ, $winsize;
 
  unless ($err) {  
    print STDERR "ERROR: ioctl on STDOUT: $!\n";
    $err = ioctl fileno(STDOUT), &TIOCGWINSZ, $winsize;
    unless ($err) {
      print STDERR "ERROR: ioctl on fileno(STDOUT): $!\n";
    } else {
      printf STDERR "ioctl on fileno(STDOUT) worked\n";
    }
  } else {
    printf STDERR "ioctl on STDOUT worked\n";
  }

  my ($rows, $cols, $unused1, $unused2) = unpack "S!4", $winsize;

  printf STDERR "(rows=%u, cols=%u)\n", $rows//0, $cols//0;

  ($maxcols, $maxrows) = ($cols || -1, $rows || -1);
}

my ($rows,$cols) = getwinsize;

print "rows=$rows, cols=$cols\n";

# vim: ts=2: sw=2


##</code><code>##

ERROR: ioctl on STDOUT: Bad address
ERROR: ioctl on fileno(STDOUT): Bad file descriptor
(rows=0, cols=0)
rows=-1, cols=-1