Function luaB_xpcall

3rd/lua-5.4.3/src/lbaselib.c:466–475

** Do a protected call with error handling. After 'lua_rotate', the ** stack will have ; so, the function passes ** 2 to 'finishpcall' to skip the 2 first values when returning results. */

** 2 to 'finishpcall' to skip the 2 first values when returning results.
*/
static int luaB_xpcall (lua_State *L) {
  int status;
  int n = lua_gettop(L);
  luaL_checktype(L, 2, LUA_TFUNCTION);  /* check error function */
  lua_pushboolean(L, 1);  /* first result */
  lua_pushvalue(L, 1);  /* function */
  lua_rotate(L, 3, 2);  /* move them below function's arguments */
  status = lua_pcallk(L, n - 2, LUA_MULTRET, 2, 2, finishpcall);
  return finishpcall(L, status, 2);
}


static int luaB_tostring (lua_State *L) {