shared_ptr.cpp

/* # shared_ptr
 *
 * Introuced in C++11, before that as part of boost.
 *
 * Reference counts usages, deletes data when the last one is gone.
 */

#include "common.hpp"

int main() {
#if __cplusplus >= 201103L
    callStack.clear();

    // First reference
    std::shared_ptr<NoBaseNoMember> sp1(new NoBaseNoMember(1));
    assert(sp1.use_count() == 1);
    assert(sp1->i == 1);

    // Create reference with copy constructor.
    std::shared_ptr<NoBaseNoMember> sp2(sp1);
    assert(sp1.use_count() == 2);
    assert(sp2->i == 1);

    // Create reference with assignment constructor.
    std::shared_ptr<NoBaseNoMember> sp3;
    sp3 = sp1;
    assert(sp1.use_count() == 3);
    assert(sp3->i == 1);

    // ERROR No converstion operator to pointer defined.
    //NoBaseNoMember *spp = sp1;

    // Replace one reference with a new pointer.
    sp1 = std::shared_ptr<NoBaseNoMember>(new NoBaseNoMember(2));
    // ERROR No constructor directly from pointers.
    //sp1 = new NoBaseNoMember(2);
    assert(sp1.use_count() == 1);
    assert(sp2.use_count() == 2);
    assert(sp1->i == 2);
    assert(sp2->i == 1);

    // Replace the remaining references and check that the destructor got called.
    sp2 = sp1;
    assert(callStack.back() != "NoBaseNoMember::~NoBaseNoMember()");
    sp3 = sp1;
    assert(callStack.back() == "NoBaseNoMember::~NoBaseNoMember()");
#endif
}