dynamic_pointer_cast.pass.cpp [plain text]
#include <memory>
#include <type_traits>
#include <cassert>
struct B
{
static int count;
B() {++count;}
B(const B&) {++count;}
virtual ~B() {--count;}
};
int B::count = 0;
struct A
: public B
{
static int count;
A() {++count;}
A(const A&) {++count;}
~A() {--count;}
};
int A::count = 0;
int main()
{
{
const std::shared_ptr<B> pB(new A);
std::shared_ptr<A> pA = std::dynamic_pointer_cast<A>(pB);
assert(pA.get() == pB.get());
assert(!pB.owner_before(pA) && !pA.owner_before(pB));
}
{
const std::shared_ptr<B> pB(new B);
std::shared_ptr<A> pA = std::dynamic_pointer_cast<A>(pB);
assert(pA.get() == 0);
assert(pA.use_count() == 0);
}
}