When must I provide a self-defined lua_lock macro(e.g: #define lua_lock(L) pthread_lock(&mutex))?

[孙世龙 sunshilong <sunshilong369@...>]

Hi, list

    In general, the macro named lua_lock is expanded as a
no-operation(i.e (void)0).

    Here is the related code snippet in Lua-5.3.5：
/*
** macros that are executed whenever program enters the Lua core
** ('lua_lock') and leaves the core ('lua_unlock')
*/
#if !defined(lua_lock)
#define lua_lock(L) ((void) 0)
#define lua_unlock(L) ((void) 0)
#endif
I wonder when I need to provide a self-defined macro (e.g:
 #define lua_lock(L) pthread_lock(&mutex))?

I would appreciate it if you could shed some light on this question.

Best regards
sunshilong