Question

I’ve applied solutions based on some search made, but the problem still there. Thank you so much for the help.

error: must use '.*' or '->*' to call pointer-to-member function ...

source code:

#include <stdio.h>

class A
{
  public:

    struct data;
    typedef int (A::*func_t)(data *);
    typedef struct data
    {
      int i;
      func_t func;
    }
    data;

    data d;

    void process()
    {
        d.func(&d);
    }

    A()
    {
        d.i = 999;
        d.func = &A::print;
    }

    int print(data *d)
    {
        printf("%d\n", d->i);
        return 0;
    }

};

int main()
{
    A *a = new A;

    a->process();

    return 0;
}

Answer 1

Your process function attempts to call d.func but it is a pointer to member function. A pointer to member function must be called on some object. Presumably you want the instance of A to be this, in which case your process function should look like:

void process()
{
    (this->*(d.func))(&d);
}

Note the use of the ->* operator to call a member function when you have a pointer to it.