Question

class Point    
{    
    int x;  
}    
static Point referencePoint;
struct Comparator
{
    bool AbsComparator(const Point& p1, const Point& p2)
    {    
        return abs(p1.x - referencePoint.x) < abs(p2.x - referencePoint.x);
    }   
};    
list<Point> points;
points.sort(Comparator::AbsComparator);

But I CANNOT use a static referencePoint for multithreading safe, is there any other way??
Thanks.

Answer 1

Make it part of Comparator:

struct Comparator
{
    Point referencePoint;

    Comparator(Point referencePoint): referencePoint(referencePoint) {}

    Comparator(const Comparator& rhs) {
        referencePoint = rhs.referencePoint;
    }

    bool operator()(const Point& p1, const Point& p2) const
    {    
        return abs(p1.x - referencePoint.x) < abs(p2.x - referencePoint.x);
    }   
};    

...

points.sort(Comparator(refP));