Function Pointer Error in C++

问题

Here is the error I am getting:

error: no matching function for call to ‘pcl::ConditionalEuclideanClustering
<pcl::Normal>::setConditionFunction(bool (EuclideanPlaneSegmentation::*)(const pcl::Normal&, const pcl::Normal&, float))’ cec.setConditionFunction(&EuclideanPlaneSegmentation::customRegionGrowing; ^ note: candidate is:/segmentation/conditional_euclidean_clustering.h:125:7:
  note: void pcl::ConditionalEuclideanClustering
  <PointT>::setConditionFunction(bool (*)(const PointT&, const PointT&, float)) [with PointT = pcl::Normal] setConditionFunction (bool (*condition_function) (const PointT&, const PointT&, float)) ^ note: no known conversion for argument 1 from ‘bool (EuclideanPlaneSegmentation::*)(const
    pcl::Normal&, const pcl::Normal&, float)’ to ‘bool (*)(const pcl::Normal&, const pcl::Normal&, float)’

Basically, I have "EuclideanPlaneSegmentation" Class and I am trying to apply this pcl tutorial:http://pointclouds.org/documentation/tutorials/conditional_euclidean_clustering.php

In tutorial, in main function

cec.setConditionFunction (&customRegionGrowing);

tries to get to the function:

    bool
    customRegionGrowing (const PointTypeFull& point_a, const   PointTypeFull&     point_b, float squared_distance)
    {
    Eigen::Map<const Eigen::Vector3f> point_a_normal = point_a.normal,        point_b_normal = point_b.normal;
    if (squared_distance < 10000)
    {
    if (fabs (point_a.intensity - point_b.intensity) < 8.0f)
      return (true);
    if (fabs (point_a_normal.dot (point_b_normal)) < 0.06)
      return (true);
  }
    else
    {
    if (fabs (point_a.intensity - point_b.intensity) < 3.0f)
    return (true);
    }
    return (false);
    }
}

I have the same function in my class and I tried:

cec.setConditionFunction(&EuclideanPlaneSegmentation::customRegionGrowing);

but it does not work. I receive the error I wrote.

In my class, if I try

cec.setConditionFunction (&customRegionGrowing);

I get this error:

/EuclideanPlaneSegmentation.cpp:402:28: error: ISO C++ forbids taking the address of an unqualified or parenthesized non-static member function to form a pointer to member function.  Say ‘&EuclideanPlaneSegmentation::customRegionGrowing’ [-fpermissive]
      cec.setConditionFunction(&customRegionGrowing);
                                ^
  /EuclideanPlaneSegmentation.cpp:402:65: error: no matching function for call to ‘pcl::ConditionalEuclideanClustering<pcl::Normal>::setConditionFunction(bool (EuclideanPlaneSegmentation::*)(const pcl::Normal&, const pcl::Normal&, float))’
      cec.setConditionFunction(&customRegionGrowing);

Does anyone have any idea what is wrong with how I can solve that problem?

回答1:

The method setConditionFunction expects a function but you are passing a member (non-static) method. Declaring the passed method static should solve the problem.

回答2:

Passing the static method works. But in case you want to dynamically reconfigure parameters in your condition you can use

setConditionFunction(boost::bind(&regularization, this, _1, _2, _3))

来源：https://stackoverflow.com/questions/29564245/function-pointer-error-in-c