I ran your benchmark and got a few warnings about "Parentheses missing around "my" list at (eval 42) line 3.", which I tracked down to the my $char in sysread test.

Strange, I cannot reproduce that. If I check man perldiag, it says:

  
       Parentheses missing around "%s" list
           (W parenthesis) You said something like

               my $foo, $bar = @_;

           when you meant
                 
               my ($foo, $bar) = @_;
                 
           Remember that "my", "our", and "local" bind tighter
           than comma.
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but there's no assignment going on here. Note that the sysopen and open lines use the same construct (using our instead of my), and there it doesn't warn. Which version of Perl are you using?

For variety, if the file is less than a couple of hundred megs, slurping the whole thing and using substr to iterate the chars is a fair bit quicker.

Welllllll, your benchmark isn't fair. All others do two things in the loop, assign a character to $char, and increment an integer. If I change the 'substr' test to:

    substr   => 'seek $fh4 => 0, SEEK_SET or die;
                 my ($char, $data);
                 sysread $fh4 => $data, -s $file;
                 $c4 = 0;
                 $char = substr $data => $c4 ++, 1 for 0 .. length ($d
+ata) - 1'
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I get the following results:

           Rate  sysread     getc   substr readline
sysread  6.48/s       --     -54%     -60%     -63%
getc     14.0/s     117%       --     -14%     -19%
substr   16.3/s     152%      16%       --      -6%
readline 17.4/s     169%      24%       7%       --
72192 : 72192 : 72192 : 72192
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Of course, the differences between substr and readline are minimal, and even getc is in the same ballpark.

Abigail