Function luaL_ctypeid 

pub unsafe extern "C-unwind" fn luaL_ctypeid(
    l: *mut lua_State,
    ctypename: *const c_char,
) -> CTypeID

Return CTypeID (FFI) of given CDATA type ctypename is a C type name as string (e.g. “struct request”, “uint32_t”, etc.).

See also: luaL_pushcdata, luaL_checkcdata