FontCache is an extension that is used by X-TrueType to cache informations about fonts.
FontCacheQueryExtension returns True if the FontCache extension is available on the given display. A client must call FontCacheQueryExtension before calling any other Xfontcache function in order to negotiate a compatible protocol version; otherwise the client will get undefined behavior (Xfontcache may or may not work).
FontCacheQueryVersion returns True if the request succeeded; the values of the major and minor protocol versions supported by the server are returned in major_versionp and minor_versionp.
FontCacheGetCacheSettings should be documented here. Returns True on success or False on failure.
FontCacheChangeCacheSettings should be documented here. Returns True on success or False on failure.
FontCacheGetCacheStatistics should be documented here. Returns True on success or False on failure.