Herb Sutter GotW89: Smart Pointers

Herb Sutter’s GotW89 Smart Pointers post includes good reasons to use make_shared/make_unique instead of naked new. Avoiding memory fragmentation is one of those:

Separate allocation

auto sp1 = shared_ptr<Widget>{ new widget{} };
auto sp2 = sp1;

Single allocation
If you use make_shared to allocate the object and the shared_ptr all in one go, then the implementation can fold them together in a single allocation.

auto sp1 = make_shared<Widget>();
auto sp2 = sp1;