int ct_timecmp( const Ct_time * t1, const Ct_time * t2 );
If the first time is greater than the second time, ct_timecmp() returns a positive number. If it is less than the the second time, it returns a negative number. If the two times are equal, ct_timecmp returns zero.
This fairly trivial comparison was needed to implement the timeout mechanism. However, unlike other code related to timeouts, the ct_timecmp function is available as a convenience even if the library is compiled with timeouts disabled. That way you can use it in other kinds of timing logic unrelated to timeouts.