G ++中的匿名函程？

Question

我有一些代码可以在VS2008中工作,但不能在G ++中工作:

struct IIterationFunctor
{
    virtual bool operator()( SStateInfo& rStateInfo ) = 0;
    virtual ~IIterationFunctor() { }
};

struct SNumItemsFunctor : public IIterationFunctor
{
    SNumItemsFunctor (uint8& nNumItems, uint8 nItemType )
        : m_nNumItems (nNumItems)
        , m_nItemType (nItemType)
    {
        m_nNumItems = 0;
    }

    virtual bool operator() ( SStateInfo& rStateInfo )
    {
        if( rStateInfo.sState.nItemType == m_nItemType )
        {
            ++m_nNumItems;
        }
        return true;
    }

    uint8& m_nNumItems;
    uint8 m_nItemType 
};

void IterateStateInfo( IIterationFunctor& functor )
{
    for (TStateInfoIterator itStateInfo = m_lstStateInfos.Begin(); 
        itStateInfo != m_lstStateInfos.End(); 
        itStateInfo++) 
    {
        SStateInfo* pStateInfo = *itStateInfo;

        // If a functor returns false don't continue processing
        if(!functor(*pStateInfo))
        {
            return;
        }
    }
}

void SomeFunction()
{
    uint8 nNumItems;
    IterateStateInfo(SNumItemsFunctor(nNumItems, 3));
}

正如我上面提到的,它适用于VS2008,但不能用G ++编译,它给出错误:错误:没有匹配函数调用'IterateStateInfo(SNumItemsFunctor)'注意:候选者是:void IterateStateInfo(IIterationFunctor&)

显然,如果我定义一个局部变量,它的工作原理如下:

void SomeFunction()
{
    uint8 nNumItems;
    SNumItemsFunctor functor(nNumItems, 3));
    IterateStateInfo(functor);
}

但有没有办法在没有局部变量的G ++(我假设C++扩展)中做到这一点？

Answer 1

问题是void IterateStateInfo( IIterationFunctor& functor )不允许接受匿名临时绑定到非const引用参数.g ++禁止它并且MSVC错误是正确的.你需要使该参数成为一个const引用,它应该工作.