Question

#include<stdio.h>
#define A(int x) printf("%d\n",x)
#define AS(A) A(20)
typedef struct{
 int *m;
 int n;
 int k;
}st;
//static st sb[10] = {AS(A)}
int main()
{
    AS(A);
    return 0;
}

I’m getting an error as below .

Line 14: error: macro parameters must be comma-separated

Please help.

Answer 1

This has nothing to do with nesting macros. The problem is

#define A(int x) printf("%d\n",x)

you must remove the int part. Like this:

#define A(x) printf("%d\n",x)

---

If you leave the int, the preprocessor interprets it as another parameter, that’s why it tells you

Line 14: error: macro parameters must be comma-separated

because expects:

#define A(int,x) printf("%d\n",x)