This function returns a compressed version of the input
data compatible with the
output of the gzip program, or FALSE if an error is
encountered. The optional parameter
level 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.
You can also give
FORCE_GZIP (the default) or
FORCE_DEFLATE as optional third paramter encoding_mode. 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.
注: level was added in PHP 4.2, before PHP 4.2 gzencode() only had the data and (optional) encoding_mode parameters..
The resulting data contains the appropriate headers and
data structure to make a standard .gz file, e.g.:
For more information on the GZIP file format, see the
document: GZIP file format specification version 4.3
(RFC 1952).
See also gzcompress().
gzuncompress(), gzdeflate(),
gzinflate().