Problem with Pointer-to-Member in Templates

I am trying to write a template that somewhat resembles how an inner class works in Java:

template class Callback{public:    Callback(T& t) : parent(t) { }    void Execute() { parent.*F(); }private:    T& parent;};

In Visual C++ 6, this complains that F is an invalid template argument, but when I remove the T and hardcode a class in as:

class Parent;template class Callback { /* ... */ };

… it works fine. Is this just a problem with VC6 or am I doing something wrong or ambiguous?

First of all, you need to parenthesize the member function invocation inside Execute() as follows:

    void Execute() { (parent.*F)(); }

Secondly, some errors may result from the way you instantiate the template. To check whether it’s a bug, try the following example. It compiles and runs successfully under C++ Builder 4.0. If your compiler still fails to compile it, it probably has a bug:

struct A{ void f() {int j =0;}};template < class T, void (T::*F)() >class Callback{public: Callback(T& t) : parent(t) { } void Execute() { (parent.*F)(); }private: T& parent;};int main(){ A a; Callback < A, &A::f > c(a); c.Execute();}

Share the Post:
Share on facebook
Share on twitter
Share on linkedin


The Latest

your company's audio

4 Areas of Your Company Where Your Audio Really Matters

Your company probably relies on audio more than you realize. Whether you’re creating a spoken text message to a colleague or giving a speech, you want your audio to shine. Otherwise, you could cause avoidable friction points and potentially hurt your brand reputation. For example, let’s say you create a

chrome os developer mode

How to Turn on Chrome OS Developer Mode

Google’s Chrome OS is a popular operating system that is widely used on Chromebooks and other devices. While it is designed to be simple and user-friendly, there are times when users may want to access additional features and functionality. One way to do this is by turning on Chrome OS

homes in the real estate industry

Exploring the Latest Tech Trends Impacting the Real Estate Industry

The real estate industry is changing thanks to the newest technological advancements. These new developments — from blockchain and AI to virtual reality and 3D printing — are poised to change how we buy and sell homes. Real estate brokers, buyers, sellers, wholesale real estate professionals, fix and flippers, and beyond may