为什么析构函数只被调用一次？ [英] Why has the destructor been called only once?

问题描述

#include <iostream>

using namespace std;

class Test
{
public:
    Test()
    {   
        printf("construct ..\n");
    }   

    ~Test()
    {   
        printf("destruct...\n");
    }   
};

Test Get()
{
    Test t = Test();
    return t;
}

int main(int argc, char *argv[])
{
    Test t = Get();
    return 0;
}

控制台输出为：

$ g++ -g -Wall -O0 testdestructor.cc
$ ./a.out 

建构..

destruct ...

destruct...

推荐答案

我想原因是在Get中返回值优化。

I suppose the reason is return value optimization in 'Get'.

a href =http://en.wikipedia.org/wiki/Return_value_optimization =nofollow> http://en.wikipedia.org/wiki/Return_value_optimization

Have a look at http://en.wikipedia.org/wiki/Return_value_optimization

实际上，你的代码不是标准的例子，但也许你的编译器也在这里应用它。

Actually your code is not the standard example, but maybe your compiler applies it here as well.

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