Hmmm, it would be a dream come true if it worked, but alas I get either nasty recursion errors or reference errors when trying this on 5.8. Basically we tie both STDOUT and STDERR to themselves and a logfile.

     tie *STDOUT, 'InstallerHandleTie', $outfile, *STDOUT;
     tie *STDERR, 'InstallerHandleTie', $outfile, *STDERR;
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InstallerHandleTie opens $outfile and saves both it's handle and STDOUT/STDERR. We override print and printf to print to the list of handles. Code shown below:

package InstallerHandleTie;

use strict;
no strict 'refs';

use FileHandle;
use Tie::Handle;
our @ISA = qw (Tie::StdHandle);
use File::Basename;
use File::Path;

my $handleId = 0;  # this is a class variable so multiple ties
                   # to same file will create different handles

sub TIEHANDLE {
   my $class = shift;
   my @handles = ();

   # see if each handle is a filename or a real handle
   foreach my $h (@_) {
      if ($h =~ /^\*/ or ref $h eq 'GLOB') {
         # it's a handle (ie *package::name) or a glob
         push @handles, $h;
         $h->autoflush(1);
      } else {
         # assume it is a file name and try to open
         # create a handle name based on
         my $hname = "_FH_$handleId";
         $handleId++;
         my $dir = dirname($h);
         if (!-e $dir or !-d $h) {
            mkpath($dir);
         }
         open($hname, ">$h") or die "unable to open file '$h': $!";
         $hname->autoflush(1);
         push @handles, $hname;
      }
   }
   return bless \@handles, $class;
}

sub PRINT {
   my $self = shift;
   my $result = 0;
   foreach my $handle (@$self) {
      $result += print $handle @_ if (fileno($handle));
   }
   return ($result == @$self);
}

sub PRINTF {
   my $self = shift;
   my $result = 0;
   foreach my $handle (@$self) {
      $result += printf $handle @_ if (fileno($handle));
   }
   return ($result == @$self);
}
1;     # required 1 to end the Perl module
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I have played around with various forms of *STDOUT{IO} etc. But as long as STDOUT or STDERR are self tied it doesn't work and I get recursion. I was able to save *STDOUT, then do a local *STDOUT, then do the tie by passing in the saved value instead of the local value and this worked. The problem came in when I tried to do the same with STDERR. In this case all the output from STDERR disappeared. If I swapped the STDERR and STDOUT ties done in this manner, I would then get STDERR output and not STDOUT.

my $gfh = *STDOUT;
my $geh = *STDERR;

foreach my $outfile (@logs) {
   local *STDOUT;
   local *STDERR;

      tie *STDOUT, 'InstallerHandleTie', $outfile, $gfh;
      tie *STDERR, 'InstallerHandleTie', $outfile, $geh;
      print "Writing to $outfile\n";
      warn "Writing warning to $outfile\n";
      untie *STDOUT;
      untie *STDERR;
}
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Doing this results in the print getting to the log file, but warn does not.

Thanks! Rick

The problem came in when I tried to do the same with STDERR. In this case all the output from STDERR disappeared. If I swapped the STDERR and STDOUT ties done in this manner, I would then get STDERR output and not STDOUT.

That's because you are essentially doing:

perl -we'open FOO, "> baz"; open BAR, "> baz"; print FOO "one\n"; prin
+t BAR "one\n";'
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where FOO and BAR have independent file pointers into the same file. If you want to share a logfile between two handles, use >> to force all writes to append at the end, or open the file outside the tie handler and pass its glob to your logger.

This works for me:

use InstallerHandleTie;

my $gfh = *STDOUT;
my $geh = *STDERR;

foreach my $outfile (qw/log1 log2/) {
        open my $outfh, ">", $outfile or die "nope: $!";

   local *STDOUT;
   local *STDERR;

      tie *STDOUT, 'InstallerHandleTie', $outfh, $gfh;
      tie *STDERR, 'InstallerHandleTie', $outfh, $geh;
      print "Writing to $outfile\n";
      warn "Writing warning to $outfile\n";
      untie *STDOUT;
      untie *STDERR;
}
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That's it! Thanks I just figured out the same thing this earlier this afternoon.


I forgot to mention that the 5.6-5.8 upgrade doc said that besides self tie of array and hash, globs also suffer from a similar problem and end up recursing. I guess I verified that one :)


Thanks for your help, it's been a great first experience with the perlmonks!