(PHP 4 >= 4.0.4, PHP 5)
gzencode — Create a gzip compressed string
$data
   [, int $level = -1
   [, int $encoding_mode = FORCE_GZIP
  ]] )   
   This function returns a compressed version of the input
   data compatible with the output of the
   gzip program.
  
For more information on the GZIP file format, see the document: » GZIP file format specification version 4.3 (RFC 1952).
dataThe data to encode.
levelThe level of compression. Can be given as 0 for no compression up to 9 for maximum compression. If not given, the default compression level will be the default compression level of the zlib library.
encoding_mode
       The encoding mode. Can be FORCE_GZIP (the default)
       or FORCE_DEFLATE. 
      
       If you use FORCE_DEFLATE, you get a standard zlib
       deflated string (inclusive zlib headers) after the gzip file header but
       without the trailing crc32 checksum.
      
   The encoded string, or FALSE if an error occurred.
  
| Version | Description | 
|---|---|
| 4.2.0 | The encoding_modeparameter was added | 
The resulting data contains the appropriate headers and data structure to make a standard .gz file, e.g.:
Example #1 Creating a gzip file
<?php
$data = implode("", file("bigfile.txt"));
$gzdata = gzencode($data, 9);
$fp = fopen("bigfile.txt.gz", "w");
fwrite($fp, $gzdata);
fclose($fp);
?>