Question

I have a function returning a local object:

class AT
{
public:
    AT() { cout<<"construct"<<endl; }

    AT(const AT& at) { cout<<"copy"<<endl; }

    ~AT() { cout<<"destroy"<<endl; }
};

AT funcAt()
{
    AT tmp;
    return tmp;
}
...
funcAt();

output is:

construct
copy
destroy
destroy

I suppose there are only construct and destroy of “tmp”, so why there is copy and another destroy? where is the copied object?

Answer 1

Because it is

1) created: AT tmp inside funcAt
2) copied: return tmp; and this is because the function returns a copy: AT funcAt()
3) destroy – the first tmp object, and the returned copy

Hint: note the copy in the output 🙂