(PHP 4, PHP 5, PHP 7, PHP 8)
gzwrite — Binary-safe gz-file write
$stream, string $data, ?int $length = null): int|false
   gzwrite() writes the contents of
   data to the given gz-file.
  
streamThe gz-file pointer. It must be valid, and must point to a file successfully opened by gzopen().
dataThe string to write.
length
       The number of uncompressed bytes to write. 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 (uncompressed) bytes written to the given gz-file 
   stream,  or false on failure.
  
| Version | Description | 
|---|---|
| 8.0.0 | lengthis nullable now; previously, the default was0. | 
| 7.4.0 | This functions returns falseon failure now; previously0was returned. | 
Example #1 gzwrite() example
<?php
$string = 'Some information to compress';
$gz = gzopen('somefile.gz','w9');
gzwrite($gz, $string);
gzclose($gz);
?>