Question

The following code:

class Something
{
public:
     ~Something()
    {
    }
};

int main()
{
    Something* s = new Something[1]; // raw pointer received from C api
    std::shared_ptr<Something> p = std::shared_ptr<Something>(s);
    std::vector<std::shared_ptr<Something>> v(&p,&p+1);

    return 0;
}

gives the following error in VS Express 2010:

---------------------------
Microsoft Visual C++ Debug Library
---------------------------
Debug Assertion Failed!

File: f:\dd\vctools\crt_bld\self_x86\crt\src\dbgdel.cpp
Line: 52

Expression: _BLOCK_TYPE_IS_VALID(pHead->nBlockUse)

For information on how your program can cause an assertion
failure, see the Visual C++ documentation on asserts.

Remove the destructor from Something and the error disappears, Why do I get this error?

Update:

Later I will have something like:

Something* s = new Something[100];

and individual shared pointers will be passed around to other objects

Answer 1

Something* s = new Something[1]; // raw pointer received from C api
std::shared_ptr<Something> p = std::shared_ptr<Something>(s); 

is incorrect usage, since

~shared_ptr();

Effects:
— If *this is empty or shares ownership with another shared_ptr instance (use_count() > 1),
there are no side effects.

— Otherwise, if *this owns an object p and a deleter d, d(p) is called.

— Otherwise, *this owns a pointer p, and delete p is called.

Default deleter is operator delete, but you have Something* s = new Something[1]; allocated by array-new operator, that should be deleted with array-delete operator (delete[]), otherwise it’s undefined behaviour. You should construct shared_ptr with specific deleter, or use something for arrays, for example boost::shared_array.

For example this code is correct.

template<typename T>
void deleter(T* p)
{
   delete[] p;
}

Something* s = new Something[1]; // raw pointer received from C api
std::shared_ptr<Something> p = std::shared_ptr<Something>(s, deleter<Something>);