LVII. Mhash Functions
These functions are intended to work with mhash. Mhash can be used to create checksums, message digests, message authentication codes, and more.
This is an interface to the mhash library. mhash supports a wide variety of hash algorithms such as MD5, SHA1, GOST, and many others. For a complete list of supported hashes, refer to the documentation of mhash. The general rule is that you can access the hash algorithm from PHP with MHASH_HASHNAME. For example, to access TIGER you use the PHP constant MHASH_TIGER.
To use it, download the mhash distribution from its web site and follow the included installation instructions.
You need to compile PHP with the --with-mhash[=DIR] parameter to enable this extension. DIR is the mhash install directory.
由于这些常量是由该扩展模块定义的，因此只有在该扩展模块被编译到 PHP 中，或者在运行时被动态加载后，这些常量才有效。
Here is a list of hashes which are currently supported by mhash. If a hash is not listed here, but is listed by mhash as supported, you can safely assume that this documentation is outdated.