#include <stdio.h>
#include <sys/ptrace.h>

int main(void)
{
  int x, n;
  n = getppid();
  if (!(x = fork())) {
    x = getppid();
    if (ptrace(PT_ATTACH, x, 0, 0)) {
      printf("traced = 1\n");
      ptrace(PT_ATTACH, n, 0, 0);
      kill(x, 9);
    }
    usleep(1000);
    ptrace(PT_DETACH, x, 0, 0);
    exit(0);
  }
  waitpid(x, &n, 0);
  printf("traced = 0\n");
  return 0;
}