How to make a variadic macro (variable number of arguments)?

Question

I want to write a macro in C that accepts any number of parameters, not a specific numberexample: #define macro( X ) something_complicated( whatever( X ) )where `X` is any number of parametersI need this because `whatever` is overloaded and can be called with 2 or 4 parameters.I tried defining the macro twice, but the second definition overwrote the first one!The compiler I'm working with is g++ (more specifically, mingw)

Answer 1

using namespace std;

#include <iostream>

#include <stdarg.h>

// inline function instead of macro : types changed to long so as to avoid compiler ambiguity error

inline double whatever( long x, long y)

{

return( (double)(x+y)/2.0f);

}

//same inline function that takes 4 arguements

inline double whatever( int x, int y, int z, int w)

{

return( (double)(x+y+z+w)/4.0f);

}

//same overloaded function that takes variable # of arguments

double whatever( int argcount, int num1, ...)

{

va_list ap;

long total;

int iNum;

double avg;

if (argcount>0)

{

total=num1;

va_start(ap,num1);

for (int iLoop=2; iLoop<=argcount; iLoop++)

{

iNum = va_arg(ap,int);

total += iNum;

}

}

va_end(ap);

avg = (double)((total*10.f)/argcount);

return(avg);

}

int main()

{

std::cout << whatever( (long)5,(long)10) << endl; //7.5

std::cout << whatever( 5,10,15,20) << endl; //12.5

std::cout << whatever ( 10, 1,2,3,4,5,6,7,8,9,10)<<endl; //55

}