Question

我在类中定义了一个纯虚函数，如下所示：

   template <typename T>
   class PositioningMethod {

   public:
       virtual ApproximatePosition *getPosition(std::list<T*> &observedRadioSignals) = 0;
   };

并在ParticleFilter中实现它，如下所示：

class ParticleFilter:public PositioningMethod<T> {

           public:
               virtual ApproximatePosition *getPosition(std::list<T*> &observedRadioSignals) {
              /*Some code and return*/
           return ApproximatePosition::from(xxxx, xxxx, xxxx());

           }
};

但是低于错误：

    "ParticleFilter<KnownBluetoothBeacon<CartesianLocation>, RadioProximity<BluetoothBeacon>
   >::getPosition(std::__1::list<RadioProximity<BluetoothBeacon>*, std::__1::allocator<RadioProximity<BluetoothBeacon>*> >&)",    referenced from:
             vtable for RadioProximityParticleFilter in lib.a(RadioProximityParticleFilter.o)
         "ParticleFilter<KnownBluetoothBeacon<CartesianLocation>, RadioProximity<BluetoothBeacon>
   >::ParticleFilter(std::__1::list<KnownBluetoothBeacon<CartesianLocation>,    std::__1::allocator<KnownBluetoothBeacon<CartesianLocation> > >&,    double)", referenced from:
             RadioProximityParticleFilter::RadioProximityParticleFilter(std::__1::list<KnownBluetoothBeacon<CartesianLocation>,    std::__1::allocator<KnownBluetoothBeacon<CartesianLocation> > >&,    double) in lib.a(RadioProximityParticleFilter.o)
       ld: symbol(s) not found for architecture arm64

我知道vtable错误通常发生在非实现的纯虚函数上，但在我的情况下它是相同的。知道我哪里错了吗？

注意： 在将我的C ++代码与iOS中的目标C集成时，我遇到的上述错误。虽然在C ++中它的工作正常

以下行导致ViewController.mm中的错误：

RadioProximityParticleFilter *obj = new RadioProximityParticleFilter (*asList,50);

Answer 1

我已经完成了您的代码，以便在我的MS VS 2013测试项目中使用它，它只是有效 - 这里是完整列表：

#include <iostream>
#include <list>

using namespace std;

class ApproximatePosition
{
public:
    static ApproximatePosition *from( int a, int b, int c)
    {
        cout << "from called." << endl;
        return NULL;
    }
};

class ListElem{};

template <typename T>
class PositioningMethod 
{
    public:
        virtual ApproximatePosition *getPosition(std::list<T*> &observedRadioSignals) = 0;
};

template <typename T>
class ParticleFilter :public PositioningMethod<T>
{

    public:
        virtual ApproximatePosition *getPosition(std::list<T*> &observedRadioSignals)
        {
            /*dummy input and return*/
            int a = 0, b = 0, c = 0;
            cout << "getPosition called." << endl;
            return ApproximatePosition::from( a, b, c );// xxxx, xxxx, xxxx());         
        }
};

int main()
{
    PositioningMethod<ListElem> *pm = new ParticleFilter<ListElem>();

    std::list<ListElem*> l;
    pm->getPosition( l );

}

输出结果为：

getPosition called.
from called.

实现纯虚方法后的vtable C ++错误

1 个答案: