boost shared_ptr: difference between operator= and reset?

Question

Are there any differences between the two pieces of code below? Is any of them preferable to the other?

operator=

boost::shared_ptr&         


        

Answer 1

Assignment operator create a new shared object from existing one, incrementing the reference count

CSharedObj& CSharedObj::operator=(CSharedObj& r) noexcept
{ 
     if(*this != r){
        //detach from the previous ownership
        if(0 == dec()) delete m_pControlObj;
        //attach to the new control object and increment the reference count
        r.inc();
        m_pControlObj = r.m_pControlObj;
    }
    return *this;
}

while the reset call doesn't create the new shared object, but rather a new ownership - attaching to the new underlying pointee ( via control object)

void CSharedObj::reset(Ptr pointee) noexcept
{
   //check if this is a last reference-detach from the previous ownership
   if(0==dec()) delete m_pControlObj;
   // create the ownership over the new pointee (refCnt = 1)
   m_pControlObj = new (std::nothrow) CControlObj(pointee);
}