static VALUE uptime_f(VALUE obj) {
	FILE *f = fopen("/proc/uptime", "r");
	if (!f) return Qnil;

	double up_f;
	char status = fscanf(f, "%lf", &up_f);
	fclose(f);

	if (status != 1) return Qnil;

	return DBL2NUM(up_f);
}
