(PHP 4 >= 4.0.4, PHP 5)
bzwrite — Binary safe bzip2 file write
$bz
   , string $data
   [, int $length
  ] )bzwrite() writes a string into the given bzip2 file stream.
bz
     The file pointer. It must be valid and must point to a file successfully opened by bzopen().
data
     The written data.
length
     
       If supplied, writing will stop after length 
       (uncompressed) bytes have been written or the end of 
       data is reached, whichever comes first.
      
   Returns the number of bytes written, or FALSE on error.
  
Example #1 bzwrite() example
<?php
$str = "uncompressed data";
$bz = bzopen("/tmp/foo.bz2", "w");
bzwrite($bz, $str, strlen($str));
bzclose($bz);
?>