Function to tell whether a debugger is attached

gistfile1.c

BOOL BWProcessIsBeingTraced()
{
  int mib[4];
	size_t bufSize = 0;
	struct kinfo_proc kp;

	mib[0] = CTL_KERN;
	mib[1] = KERN_PROC;
	mib[2] = KERN_PROC_PID;
	mib[3] = getpid();

	bufSize = sizeof (kp);
	if (sysctl(mib, 4, &kp, &bufSize, NULL, 0) < 0) 
	{
		return 0;
	}
	return ((kp.kp_proc.p_flag & P_TRACED) != 0);
}