Function luaD_callhook

lua/ldo.c:182–206

void luaD_callhook (lua_State *L, int event, int line) {
  lua_Hook hook = L->hook;
  if (hook && L->allowhook) {
    ptrdiff_t top = savestack(L, L->top);
    ptrdiff_t ci_top = savestack(L, L->ci->top);
    lua_Debug ar;
    ar.event = event;
    ar.currentline = line;
    if (event == LUA_HOOKTAILRET)
      ar.i_ci = 0;  /* tail call; no debug information about it */
    else
      ar.i_ci = cast_int(L->ci - L->base_ci);
    luaD_checkstack(L, LUA_MINSTACK);  /* ensure minimum stack size */
    L->ci->top = L->top + LUA_MINSTACK;
    lua_assert(L->ci->top <= L->stack_last);
    L->allowhook = 0;  /* cannot call hooks inside a hook */
    lua_unlock(L);
    (*hook)(L, &ar);
    lua_lock(L);
    lua_assert(!L->allowhook);
    L->allowhook = 1;
    L->ci->top = restorestack(L, ci_top);
    L->top = restorestack(L, top);
  }
}


static StkId adjust_varargs (lua_State *L, Proto *p, int actual) {