Hi Jeff,

...

According the comments in one of the headers constructing a "time_period" with zero duration is not possible; i.e. the duration is at least 1.

Where is this?

It's in file "period.hpp" after line 35.

I believe I agree, but it is going to take awhile to evaluate the impact. In the meantime, I recommend using is_null() to avoid this. Or if you want to take a crack at changing the logic on your own it is really a matter of modifying the date_time/period.hpp file.

Well I already changed period.hpp for me. That's what I did: 1. Replaced member "last_" by new one called "end_" which now stores the next point in time not belonging to the period. 2. Changed all methods, operators and constructors to use the new variable correctly. 3. Added a new constructor which accepts just a "ptime" as argument. Unfortunately I couldn't make regression tests to ensure that this change doesn't have any negative side effects. Regards, Frank ps: is_adjacent() is using method "begin()" where it could use "begin_" instead which might be more efficient. ******************************************* Diese E-Mail enthaelt vertrauliche und/oder rechtlich geschuetzte Informationen. Wenn Sie nicht der richtige Adressat sind oder diese E-Mail irrtuemlich erhalten haben, informieren Sie bitte sofort den Absender und loeschen Sie diese Mail. Das unerlaubte Kopieren sowie die unbefugte Weitergabe dieser Mail ist nicht gestattet. This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorised copying, disclosure or distribution of the contents in this e-mail is strictly forbidden. *******************************************