Function luaL_getmetafield

3rd/lua-5.4.3/src/lauxlib.c:845–858

LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) {
  if (!lua_getmetatable(L, obj))  /* no metatable? */
    return LUA_TNIL;
  else {
    int tt;
    lua_pushstring(L, event);
    tt = lua_rawget(L, -2);
    if (tt == LUA_TNIL)  /* is metafield nil? */
      lua_pop(L, 2);  /* remove metatable and metafield */
    else
      lua_remove(L, -2);  /* remove only metatable */
    return tt;  /* return metafield type */
  }
}


LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {