(PHP 4 >= 4.0.4, PHP 5, PHP 7)

gzencodeCreate a gzip compressed string


gzencode ( string $data [, int $level = -1 [, int $encoding = ZLIB_ENCODING_GZIP ]] ) : string|false

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).



The data to encode.


The 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.


The encoding mode. Can be FORCE_GZIP (the default) or FORCE_DEFLATE.

Prior to PHP 5.4.0, using FORCE_DEFLATE results in a standard zlib deflated string (inclusive zlib headers) after a gzip file header but without the trailing crc32 checksum.

In PHP 5.4.0 and later, FORCE_DEFLATE generates RFC 1950 compliant output, consisting of a zlib header, the deflated data, and an Adler checksum.

Return Values

The encoded string, or false if an error occurred.


The resulting data contains the appropriate headers and data structure to make a standard .gz file, e.g.:

Example #1 Creating a gzip file

$data = implode("", file("bigfile.txt"));
$gzdata = gzencode($data, 9);
$fp = fopen("bigfile.txt.gz", "w");
fwrite($fp, $gzdata);

See Also

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