Re: Very confused by Ada tasking, can not explain the execution outcome.

[Georg Bauhaus <rm.tsoh.plus-bug.bauhaus@maps.futureapps.de>]

climber.cui@gmail.com wrote:
> On Aug 30, 1:12 am, "Jeffrey R. Carter"

>> If an exception occurs in your task, the task will terminate silently. This is a
>> way your task and program could terminate although it never increments Rounds
>> nor executes its final statement.

> Thanks Jeff. It seems you are right.  Some exceptions occurs during
> the task execution, and Ada is ignoring it.

Ada is not actually ignoring exceptions in tasks; the program
is following the Ada rules: Add these lines,

      Put_Line("TASK EXITS ::  rounds =" & INTEGER'Image(rounds) &
        "...." );

   exception
      when X: others =>
         Put_Line("TASK failed due to " &
           Ada.Exceptions.Exception_Information(X));
   end User_thread;

and you should see something like
TASK failed due to Exception name: CONSTRAINT_ERROR
Message: multi_res_alloc_a.adb:131 index check failed

So, yes,
> It is very likely to the
> 'array index out of bound'.



>  I doubt that Ada follows the strict
> evaluation rules when it evaluates the boolean expressions,

you would specify short circuit evaluation using "and then"
etc. as explained by Damien Carbonne;  Ada follows the rules
defined in the LRM, section

 "4.5.1 Logical Operators and Short-circuit Control Forms"