Function c4db_getUUIDs 

pub unsafe extern "C" fn c4db_getUUIDs(
    database: *mut C4Database,
    publicUUID: *mut C4UUID,
    privateUUID: *mut C4UUID,
    outError: *mut C4Error,
) -> bool

Returns the database’s public and/or private UUIDs. (Pass NULL for ones you don’t want.)