sub topdf(filename);

sub topdf {
    # Get the filename argument...
    my $filename = shift;

    # Make stdout unbuffered...
    select(STDOUT); $| = 1;

    # Write the content type to the client...
    print "Content-Type: application/pdf\n\n";

    # Run HTMLDOC to provide the PDF file to the user...
    system "htmldoc -t pdf --quiet --webpage $filename";
}