valgrind does not complain for memory corruption?

Question

I have a small block of code as blow

class singler
{
    private:
        singler() { _id = id++; };
    public:
        ~singler() { cout<<"In destructor of "<<_id<<endl;};
        static singler* allocate() { singler* p = new singler(); return p; };
        static int id;
        int _id;
};
int singler::id = 0;
singler& create_new(singler*& ptr)
{
    singler * p = singler::allocate();
    ptr = p;
    return (*p);
}
int main()
{
    singler* ptr;
    singler obj = create_new(ptr);
    delete ptr;
}

So you can see that the destructor of the object will be called twice, as a proof, i compiled and ran it, it gave output as

In destructor of 0
In destructor of 0

Problem is in valgrind, it does not complain for anything, the valgrind output is as below ==2

0408== Memcheck, a memory error detector
==20408== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==20408== Using Valgrind-3.5.0 and LibVEX; rerun with -h for copyright info
==20408== Command: a.out
==20408==
In destructor of 0
In destructor of 0
==20408==
==20408== HEAP SUMMARY:
==20408==     in use at exit: 0 bytes in 0 blocks
==20408==   total heap usage: 1 allocs, 1 frees, 4 bytes allocated
==20408==
==20408== All heap blocks were freed -- no leaks are possible
==20408==
==20408== For counts of detected and suppressed errors, rerun with: -v
==20408== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 4 from 4)

So how to detect this type of errors efficiently? ( i mean using some tool which will atleast tell me if there is any problem, and if yes, where is it? )

Answer 1

There are no corruption in your program, and valgrind worked fine in your case.

Two objects are indeed created. The first object is allocated on a heap, and the second is a copy of the first object. That is why you see the destructor called twice.