The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
FORCE_GZIP
(int) FORCE_DEFLATE
(int) ZLIB_ENCODING_RAW
(int) ZLIB_ENCODING_DEFLATE
(int) ZLIB_ENCODING_GZIP
(int) ZLIB_FILTERED
(int) ZLIB_HUFFMAN_ONLY
(int) ZLIB_FIXED
(int) ZLIB_RLE
(int) ZLIB_DEFAULT_STRATEGY
(int) ZLIB_BLOCK
(int) ZLIB_NO_FLUSH
(int) ZLIB_PARTIAL_FLUSH
(int) ZLIB_SYNC_FLUSH
(int) ZLIB_FULL_FLUSH
(int) ZLIB_FINISH
(int)