int gzwrite (int zp, string string [, int
length])
Gzwrite() writes the contents of string to the gz-file stream pointed to by zp. If the length argument is given, writing will stop after length (uncompressed) bytes have been written or the end of string is reached, whichever comes first.
Note that if the length argument is given, then the magic_quotes_runtime configuration option will be ignored and no slashes will be stripped from string.