[Lazarus] Date value "0"

[Mark Morgan Lloyd]

Michael Schnell wrote:
> On 05/27/2015 11:05 AM, Mark Morgan Lloyd wrote:
>>
>>
>> No it can't. You have to be prepared to parse 12:00 a.m. by context 
>> but it's usually midnight.
>>
> Of which day the one that also has 0:pm or of the previous ?

Wp "12-hour clock" shows 11:59 p.m. followed by 12:00 a.m., but I'm not 
100% confident in this and sometimes you just have to guess :-)

Of course there's the interesting case where there's a leap second as 
well, because anybody foolish enough to insist on the 12 hour clock 
would see something like 11:59:59 11:59:60 p.m. 12:00:00 a.m.

Anybody with the least bit of sense uses ISO-8601 and 24-hour clock, but 
it's still possible to get into deep water when one gets things like 
astronomical observations or timezone offsets. Unfortunately there's a 
lot of legacy data and embedded kit floating around where timestamps are 
reported as BCD plus flag bits, and in particular there's things like 
(derivatives of) the 146818 chip which are both buggy and flexible 
enough that a firmware writer can make every conceivable bad decision 
leaving a heck of a mess for the poor so-and-do who has to make sense of 
logged data remotely.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]