A hook has type lua_Hook, defined as follows:

func is the hook. mask specifies on which events the hook will be called: It is formed by a disjunction of the constants , LUA_MASKRET, LUA_MASKLINE, and LUA_MASKCOUNT. The count argument is only meaningful when the mask includes LUA_MASKCOUNT. For each event, the hook is called as explained below:

You can get the current hook, the current mask, and the current count with the following functions:

While Lua is running a hook, it disables other calls to hooks. Therefore, if a hook calls back Lua to execute a function or a chunk, that execution occurs without any calls to hooks.