在调用过程中,是否要销毁/删除std :: function是未定义的行为？
class Event {
public:
Event(std::function<void()> f) : func(std::move(f)) {}
~Event() {}
std::function<void()> func;
};
int main()
{
std::vector<Event> events;
auto func = [&]() {
events.pop_back();
std::cout << "event" << std::endl;
// do more work
};
events.emplace_back(std::move(func));
events[0].func();
return 0;
}
解决方法
这是
[res.on.objects]p2未定义的：
@H_403_9@If an object of a standard library type is accessed,and the beginning@H_403_9@在这种情况下,“访问”包括对std :: function的函数调用操作符的调用. std :: function对象的生命周期在pop_back()调用结束时,在访问过程中结束.因此,访问不会在对象生命周期结束之前发生,并且行为未定义.
of the object’s lifetime does not happen before the access,or the
access does not happen before the end of the object’s lifetime,the
behavior is undefined unless otherwise specified.
