Function auxupvalue

Source/Misc/lua/src/lua.c:11695–11705

static int auxupvalue (lua_State *L, int get) {
const char *name;
int n = luaL_checkint(L, 2);
luaL_checktype(L, 1, LUA_TFUNCTION);
if (lua_iscfunction(L, 1)) return 0;  /* cannot touch C upvalues from Lua */
name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
if (name == NULL) return 0;
lua_pushstring(L, name);
lua_insert(L, -(get+1));
return get + 1;
}


static int db_getupvalue (lua_State *L) {