use IO::Compress::Gzip qw(gzip $GzipError);

  my $compressed;
  if(gzip \$foo => \$compressed [,OPTS]){
   # Compressed version of $foo stored in $compressed
  }

##</code><code>##

  # assume $fh is a filehandle
  ...
  gzip \$foo => $fh

##</code><code>##

  gzip \$foo => "-"