[Lazarus] EpikTimer v1.0.1 released

[Michael Schnell]

On 05/24/2014 01:55 PM, Graeme Geldenhuys wrote:
>
> I applied some of my changes to code in Github (more changes recently
> discussed in this mailing list will follow soon), fixed the "etdemo"
> project to be compilable again, updated the demo to use FPC Resources
> instead of the old *.lrs files.

Great !

As EpikTimer internals seem to be discussed here rather than in 
fc-devel, I add some comments in this thread.

I use EpikTimer in my (soon to be released) work on the ActiveNoGUI 
Widget Type.

Here I found, that it is a rather appropriate use for EpikTimer to 
handle it in a "static" way, not creating an instance of TEpikTimer with 
every use of same, but simply to use class properties, class procedures 
and class functions of TEpikTimer.

To allow for this, during the weekend,  I modified the (not absolutely 
latest) version of epiktimer.pas in a very straight forward manner, just 
defining some variables as "class var", and adding "class" to some 
properties, procedures and functions.

Moreover I moved the function "InitTimebases" out of the creator and 
made it to be a private "class procedure TEpikTimer.InitTimebases;"

Also TEpikTimer.InitTimebases is called in an initialization section of 
the EpikTimer unit.


The advantage of this is that the overhead when creating an EpikTimer is 
reduced to zero.

The only disadvantage I see is is, that with that modification, 
different instances of TEpikTimer don't have their own tuning 
parameters, as they are calculated only in the initializing phase of the 
application.

Hence deriving siblings of TEpikTimer and overloading the virtual functions
SystemSleep, CalibrateCallOverheads, and CalibrateTickFrequency
does not seem to make sense.

(In fact I am not sure, what happens when deriving siblings of 
TEpikTimer, as I am astonished that doing things like "class function 
SystemSleep(Milliseconds: Integer):integer; Virtual;" is even possible. 
I fail to understand how a virtual class function is supposed to work, 
as I understand that without an instance there is no virtual message table.)

Is deriving siblings of TEpikTimer and overloading the virtual functions 
SystemSleep, CalibrateCallOverheads, and CalibrateTickFrequency really a 
viable feature of EpikTimer ? If yes, I am sure that I can find a way to 
combine it with the static usability I introduced.

If you want me to, I of course can provide an appropriately modified 
version of epiktimer.pas derived from the version you tell me you 
consider stable.

Thanks for listening,
-Michael