call functions that share one argument without indicating what the argument is repeatedly.

gistfile1.c

#include <cstdio>

void print3arg(int a, int b, int c)
{
	printf("a=%d, b=%d, c=%d\n", a, b, c);
}

void print2arg(int a, int b)
{
	printf("A=%d, B=%d\n", a, b);
}

int main()
{

#define _EXEC(FUNC, ...)	FUNC(arg, __VA_ARGS__)
	int arg = 1;
	_EXEC(print3arg, 2, 3);
	_EXEC(print2arg, 4);
	{
		int arg = 2;
		_EXEC(print3arg, 2, 3);
		_EXEC(print2arg, 4);
	}
	_EXEC(print2arg, 4);
#undef _EXEC
	
	return 0;
}