>>616
基本的には、ちゃんと動いたぞ？
まあ、マクロの書き方としては不十分だが。
--------------------------------------------------
#define ISUNSIGNED(a) (0 <= (a) && 0 <= ~(a))
main () {
  signed int s = 123;
  unsigned int u = 123;
  printf ("signed %d\n", ISUNSIGNED(s));
  printf ("unsigned %d\n", ISUNSIGNED(u));
}
--------------------------------------------------
signed 0
unsigned 1
--------------------------------------------------