我应该分配还是重置unique_ptr？

Question

Given the common situation where the lifespan of an owned object is linked to its owner, I can use a unique pointer one of 2 ways . .

It can be assigned:

class owner
{
    std::unique_ptr<someObject> owned;    
public:
    owner()
    {
        owned=std::unique_ptr<someObject>(new someObject());        
    }
};

The reset method can be utilised:

class owner
{
    std::unique_ptr<someObject> owned;    
public:
    owner()
    {
        owned.reset(new someObject());
    }
};

In the interests of best practice, should I prefer one form over the other?

EDIT: Sorry folks. I over simplified this. The heap allocation occurs in an initialise method and not in the ctor. Therefore, I cannot use initialiser lists.

Answer 1

From the docs of unique_ptr 's operator= :

Transfers ownership of the object pointed to by r to *this as if by calling reset(r.release()) followed by an assignment from std::forward<E>(r.get_deleter()) .

And all you need of that is the reset call, so it's simpler to just call it directly

Answer 2

The proper way to do this (that you didn't list) is to use the constructor of owned :

owner() : owned(new someObject())
{}

Apart from that I'd prefer reset as you don't create a useless intermediate instance in that case (even though there might be no difference on the machine level as the optimizer can do a lot there).