typedef int (* initModuleProc)(int);
 
initModuleProc pProc = nullptr;
std::function<int (int)> m_pInit;
 
m_pInit = pProc;
std::cout << !pProc << std::endl;   // True
std::cout << !m_pInit << std::endl; // False,even though it's clearly assigned a nullptr
m_pInit = nullptr;
std::cout << !m_pInit << std::endl; // True

我写了这个辅助函数来解决这个问题.

template<typename T>
void AssignToFunction(std::function<T> &func,T* value)
{
    if (value == nullptr)
    {
        func = nullptr;
    }
    else
    {
        func = value;
    }
}