Re: Ada, games and frame rate calculation

[tmoran@acm.org]

> You can read the clock with microsecond precision (on Windows and some
> other platforms); you can only delay with an accuracy of about 10
> milliseconds (again on Windows).
   That depends on how you delay.  There are Windows calls for delays, but
you can also have a spin delay whose accuracy is limited by the clock
tick, clock reading time, and maximum delay caused by other tasks.
  e.g.
   Go_Time := Ada.Calendar.Clock+0.000_058;  -- delay 58.0 microseconds
   while Ada.Calendar.Clock < Go_Time loop delay 0.0;end loop;
(But note this can fail on some motherboards where the clock jumps forward
several seconds if you re-read it too fast.)  Most, but IIRC not all,
compilers' run-times will do a "delay 0.0;" very fast if nothing else
needs to run.
  I believe the Janus system calls Windows for long delays but does its
own task management for short delays.