Use a `unique_ptr<T>` to hold pointers

Reason

Using std::unique_ptr is the simplest way to avoid leaks. It is reliable, it makes the type system do much of the work to validate ownership safety, it increases readability, and it has zero or near zero run-time cost.

Example

void use(bool leak)
{
    auto p1 = make_unique<int>(7);   // OK
    int* p2 = new int{7};            // bad: might leak
    // ... no assignment to p2 ...
    if (leak) return;
    // ... no assignment to p2 ...
    vector<int> v(7);
    v.at(7) = 0;                    // exception thrown
    delete p2;                      // too late to prevent leaks
    // ...
}

If leak == true the object pointed to by p2 is leaked and the object pointed to by p1 is not. The same is the case when at() throws. In both cases, the delete p2 statement is not reached.

Enforcement

Look for raw pointers that are targets of new, malloc(), or functions that might return such pointers.