Fantastic -- thanks, that's exactly what I needed. BTW, I think the $2 should have been a $1. It works for me on both Linux and FreeBSD. The following is what I ended up with.

# Normally returns the number of columns on the output tty.
# Return 0 if output isn't a tty.
# Returns undef if it's unable to find the width.
sub tty_columns {
  return 0 unless -t STDOUT;

  my $result;

  # The following works on linux, but seems to fail on freebsd.
  # It works properly if the user resizes the terminal window while th
+e program is running.
  if (eval "require 'sys/ioctl.ph'") {
    eval {
      # All of the dies on the next few lines will be caught by the ev
+al{}.
      die unless defined &TIOCGWINSZ;
      open(TTY, "+</dev/tty") or die;
      die unless ioctl(TTY, &TIOCGWINSZ, $winsize='');
      my ($row, $col, $xpixel, $ypixel) = unpack('S4', $winsize);
      $result = $col;
    }
  }
  return $result if defined $result;

  # A less efficient fallback, should work on anything unixy.
  chomp(my @lines = `stty -a`);
  my ($rows, $columns);
  for (@lines) {
      $rows = $1 if /rows (\d+);/;       # linux
      $rows = $1 if /(\d+) rows;/;       # FreeBSD
      $columns = $1 if /columns (\d+);/; # linux
      $columns = $1 if /(\d+) columns;/; # FreeBSD
  }
  return $columns if defined $columns;

  # The following two methods give us a fighting chance on a non-POSIX
+ system. I don't use them as the defaults
  # because I don't want to introduce dependencies.

  # http://search.cpan.org/~kjalb/TermReadKey/ReadKey.pm
  # Term::ReadKey is not a standard Perl module, and may not be instal
+led. If the user resizes the terminal
  # while the program is running, this will correctly reflect the resi
+zing.
  eval 'use Term::ReadKey; my ($wchar, $hchar, $wpixels, $hpixels) = G
+etTerminalSize(); $result=$wchar';
  return $result if defined $result;

  # http://search.cpan.org/~nwclark/perl-5.8.8/lib/Term/ReadLine.pm
  # Term::ReadLine is a standard Perl module, but exists in different 
+implementations under the hood. On a Linux
  # system, it's implemented using Term::ReadLine::Gnu, which supports
+ get_screen_size(). On a default FreeBSD system,
  # however, the following won't work; you'd have to install the p5-Re
+adLine-Gnu package to get support for this function.
  eval 'use Term::ReadLine; $term = new Term::ReadLine("foo"); my ($r,
+$c)= Term::ReadLine::get_screen_size(); $result=$c';
  return $result if defined $result;

  return undef;
}

[download]

In reply to Re^2: bulletproof way of finding size of terminal? by bcrowell2
in thread bulletproof way of finding size of terminal? by bcrowell2

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.