Method use_count

src/fl/stl/weak_ptr.h:132–134

Observers

    
    // Observers
    long use_count() const FL_NOEXCEPT {
        return mControlBlock ? static_cast<long>(mControlBlock->shared_count) : 0;
    }
    
    bool expired() const FL_NOEXCEPT { 
        return use_count() == 0;