Re: Ada 95 Timers: Any Alternatives Available, Storage, Efficiency, Reliability, Accuracy, Et Cetera Issues?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 2019-05-30 17:34, Niklas Holsti wrote:
> On 19-05-30 16:57 , Felix_The_Cat@gmail.com wrote:
>>
>> What are the limitations of the "with Timer;" in Ada 95?
> 
> Not understood. There is no standard "package Timer" in Ada 95 (nor 
> other Ada standards, AFAIK).

It looks that the OP meant Ada.Execution_Time.Timers.

>> I want to simply do something in the Ada code when the timer
>> counts down to 0.
> 
> That sounds like some HW timer. Normally you would not use those 
> directly, but instead use the "delay" or "delay until" statements, to 
> wait until the actual time when something should be done, and let the 
> compiler and run-time system handle the HW timers.

Right, alternatives could also be timed entry call (9.7.2) and delay 
alternative of selective accept (9.7.1).

As for limitations of Ada.Execution_Time.Timers they are from the SW 
design POV. Scheduled actions usually interact with the program logic, 
the states of program objects, the context of the task performing these 
actions. Ada.Execution_Time.Timers are too low-level for a that.

The intended use of Ada.Execution_Time.Timers is for something quite 
decoupled from the program itself, e.g. I can imagine a system health 
monitoring based on Ada.Execution_Time.Timers.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de