QSharedPointer::create()

Question

In Qt 4 i have I have the following array:

QSharedPointer<unsigned char> encrypted(new unsigned char[RSA_size(publickey)]);

How can I combine the two allocations in one with the new Qt 5 create function?

QSharedPointer<T> QSharedPointer::create()

Answer 1

Your first example is wrong and will not only leak memory, but cause UB. When you define a QSharedPointer<unsigned char> you are defining a smart pointer for a single element, not an array of elements, therefore delete will be called, not delete[].

Change it to:

QSharedPointer<unsigned char> encrypted(new unsigned char[RSA_size(publickey)], [](unsigned char* x){ delete[] x; });

That is: you have to provide a custom deleter for the pointer.

Finally, the QSharedPointer::create function is supposed to be used only for one element, not an array of elements and it can be used with:

auto x = QSharedPointer<unsigned char>::create();