Ada.Real_Time Vs. Ada.Calendar

Ada.Real_Time Vs. Ada.Calendar

[markp]

I need to compare data types that are stored in Ada.Real_Time.Time and
Ada.Calendar.Time. I know I can get a seconds count from each package.
However, is it the same time base? Is it dependant on the hardware it
is run on?

Re: Ada.Real_Time Vs. Ada.Calendar

[Jeffrey R. Carter]

markp wrote:
> I need to compare data types that are stored in Ada.Real_Time.Time and
> Ada.Calendar.Time. I know I can get a seconds count from each package.
> However, is it the same time base? Is it dependant on the hardware it
> is run on?

In general, you can't count on them having any meaningful relationship. 
Real_Time may be a count of ticks since the program started, for 
example, while Calendar must be a date and time CE.

How they are implemented is not specified, which is not surprising.

For a specific compiler and platform, you may be able to make use of 
compiler-dependent information to relate the two. GNAT, for example, 
defines both Time types as "new Duration". That doesn't guarantee that 
the stored values have the same meaning, though.

-- 
Jeff Carter
"We burst our pimples at you."
Monty Python & the Holy Grail
16

Re: Ada.Real_Time Vs. Ada.Calendar

[Simon Wright]

"Jeffrey R. Carter" <spam.not.jrcarter@acm.not.spam.org> writes:

> In general, you can't count on them having any meaningful
> relationship. Real_Time may be a count of ticks since the program
> started, for example, while Calendar must be a date and time CE.

And I don't think it would be right to expect the relationship to be
constant, either -- Ada.Calendar might be synchronised with an
external time shource and might not be monotonic, whereas Real_Time
ought to be monotonic.