I have function which is copying some value to objects i'll pass.
So, Something like this
void functionReturnObjects(int* ptr);
I'll call above function like this
std::shared_ptr<int> sp( new int[10], std::default_delete<int[]>() );
functionReturnObjects(sp.get()); => so this will copy int objects to sp.
Now, I want to take individual shared ptr from the above 10 and want to make separate copy or want to shared it with some other shared ptr.
So something like
std::shared_ptr<int> newCopy = sp[1] ==> This is not working I am just showing what I want.
Basically I want to transfer ownership from 10 shared pointer to new individual shared ptr without allocating new memory.
Please let me know if the questions is not clear.
Use std::shared_ptr
's aliasing constructor (overload #8):
template< class Y > shared_ptr( const shared_ptr<Y>& r, element_type *ptr );
std::shared_ptr<int> newCopy(sp, sp.get() + 1);
This will make newCopy
and sp
share ownership of the entire array created with new int[10]
, but newCopy.get()
will point to the second element of said array.
In C++17 this can instead look like the following if you happen to find it more readable:
std::shared_ptr newCopy(sp, &sp[1]);