Keep track of macro expansion

Question

I want to keep track of macro expansion - how many times the macro has been expanded and what are the args when expansion happened.

For example,

I have a macro might look like this:

#define mymacro(x) int x

and in my code I have something like this:

mymacro(a);
mymacro(b);

in the end of the preprocessor expansion (oh yeah, is there a way to make a specific macro to become the last to expand?), I would like to know how many times mymacro has been used and what are the args passed. In this case, it would be 2 times, and args would be a and b.

I was investigating boost-preprocessor lib. They have BOOST_PP_ARRAY, but I don't know how to make it "static", so that I can use it in later.

I found something in the BOOST_PP_COUNTER. It looks like the BOOST_PP_COUNTER is something that can maintain its state in preprocessor phrase. But I am still unclear how to do what I wanted.

Answer 1

How about something like this?

#include <iostream>

int m_counter = 0;
const char *m_arguments[32] = { 0 };

#define COUNT_M(a) m_arguments[m_counter++] = #a;
#define M(a) COUNT_M(a) int a

int main()
{
    M(x);
    M(y);

    for (int i = 0; i < m_counter; i++)
    {
        std::cout << "m_arguments[" << i << "] = \"" << m_arguments[i] << "\"\n";
    }
}