use Compress::Zlib ;
    
    # use stdin if no files supplied
    @ARGV = '-' unless @ARGV ;
    
    foreach my $file (@ARGV) {
        my $buffer ;
    
        my $gz = gzopen($file, "rb") 
             or die "Cannot open $file: $gzerrno\n" ;
    
        print $buffer while $gz->gzread($buffer) > 0 ;
    
        die "Error reading from $file: $gzerrno" . ($gzerrno+0) . "\n" 
            if $gzerrno != Z_STREAM_END ;
        
        $gz->gzclose() ;
    }

Below is a script which makes use of C<gzreadline>. It implements a
very simple I<grep> like script.

    use strict ;
    use warnings ;
    
    use Compress::Zlib ;
    
    die "Usage: gzgrep pattern [file...]\n"
        unless @ARGV >= 1;
    
    my $pattern = shift ;
    
    # use stdin if no files supplied
    @ARGV = '-' unless @ARGV ;
    
    foreach my $file (@ARGV) {
        my $gz = gzopen($file, "rb") 
             or die "Cannot open $file: $gzerrno\n" ;
    
        while ($gz->gzreadline($_) > 0) {
            print if /$pattern/ ;
        }
    
        die "Error reading from $file: $gzerrno\n" 
            if $gzerrno != Z_STREAM_END ;
        
        $gz->gzclose() ;
    }

This script, I<gzstream>, does the opposite of the I<gzcat> script
above. It reads from standard input and writes a gzip data stream to
standard output.

    use strict ;
    use warnings ;
    
    use Compress::Zlib ;
    
    binmode STDOUT;  # gzopen only sets it on the fd
    
    my $gz = gzopen(\*STDOUT, "wb")
          or die "Cannot open stdout: $gzerrno\n" ;
    
    while (<>) {
        $gz->gzwrite($_) 
          or die "error writing: $gzerrno\n" ;
    }

    $gz->gzclose ;

=head2 Compress::Zlib::memGzip

This function is used to create an in-memory gzip file with the minimum
possible gzip header (exactly 10 bytes).

    $dest = Compress::Zlib::memGzip($buffer) ;

If successful, it returns the in-memory gzip file, otherwise it returns
undef.

The C<$buffer> parameter can either be a scalar or a scalar reference.

See L<IO::Compress::Gzip|IO::Compress::Gzip> for an alternative way to
carry out in-memory gzip compression.

=head2 Compress::Zlib::memGunzip

This function is used to uncompress an in-memory gzip file.

    $dest = Compress::Zlib::memGunzip($buffer) ;

If successful, it returns the uncompressed gzip file, otherwise it
returns undef.

The C<$buffer> parameter can either be a scalar or a scalar reference. The
contents of the C<$buffer> parameter are destroyed after calling this function.

See L<IO::Uncompress::Gunzip|IO::Uncompress::Gunzip> for an alternative way
to carry out in-memory gzip uncompression.