我遇到了一个非常奇怪的问题,我已经将其缩小为以下测试用例:
#include <iostream>
#include <map>
#include <string>
struct Test
{
std::map<std::string, void (Test::*)()> m;
Test()
{
this->m["test1"] = &Test::test1;
this->m["test2"] = &Test::test2;
}
void test1() { }
void test2() { }
void dispatch(std::string s)
{
if (this->m.at(s) == &Test::test1)
{ std::cout << "test1 will be called..." << std::endl; }
else if (this->m.at(s) == &Test::test2)
{ std::cout << "test2 will be called..." << std::endl; }
(this->*this->m.at(s))();
}
};
int main()
{
Test t;
t.dispatch("test1");
t.dispatch("test2");
}
输出结果为
当启用优化时,将会调用test1...
将会调用test1...
这是非常奇怪的。发生了什么?