구조체 멤버 변수 이름을 함수의 인자로 전달할 수 있나요?

#include <stdio.h>
#include <stddef.h>
 
struct test
{
  int a;
  int b;
};
 
void foo( struct test t1, struct test t2, size_t offset ) {
    int t1_member = *((int *)((char *)&t1 + offset));
    int t2_member = *((int *)((char *)&t2 + offset));
 
    if ( t1_member > t2_member ) {
        printf("t1 > t2\n");
    }
    else if ( t1_member < t2_member ) {
        printf("t1 < t2\n");
    }
    else {
        printf("t1 = t2\n");
    }
}
 
int main() {
    struct test t1 = { 10, 20 };
    struct test t2 = { 30, 5 };
 
    foo(t1, t2, offsetof(struct test, a));
    foo(t1, t2, offsetof(struct test, b));
}

    int t1_member = aux == 'a' ? t1.a : t1.b ;