Re: 4 beginner's questions on the PL Ada

["Randy Brukardt" <randy@rrsoftware.com>]

"Jeffrey Carter" <spam.jrcarter.not@spam.not.acm.org> wrote in message 
news:ku3opa$svn$3@dont-email.me...
> On 08/09/2013 02:38 PM, Emanuel Berg wrote:
>>
>> Yes! This works great:
>>
>> with Ada.Task_Identification;
>> use  Ada.Task_Identification;
>>
>> Task_Name : constant String := Image(Current_Task);
>>
>> It produces output like
>>
>> add_one_081838Dt
>>
>> if the task is referred to as Add_One in the code.
>
> Not necessarily. First, this is only available in compilers that choose to 
> implement the optional Annex C, Systems Programming, so this is 
> non-portable.

That's formally true, but practically, I don't know of any Ada compilers 
that don't implement Ada.Task_Identification. An Ada compiler vendor needs 
something like it for debugging tasking programs, and it would be silly to 
create something different for that job.

> Second, the contents of the string returned by Image are implementation 
> defined. One particular compiler uses the task name as part of the 
> returned value, but others might not, so adding another layer of 
> non-portability.

Right. Janus/Ada uses "@nnnn", where "nnnn" is a task number (they're all 
assigned integers by our task supervisor). The task supervisor doesn't know 
anything about the names used in the program (its much lower level than 
that).

But the *real* problem is having a unique identification for each task 
without having to worry about the task type. There might an additional level 
of work to figure out which task object is associated with which identifier 
string, but that's easily handled by printing out the id for each task when 
it starts.

                                Randy.