Illegal declaration in task definition

Question

I have the following task specification:

with Ada.Real_Time; use Ada.Real_Time;

package pkg_task is
    task type task_t is
        activationTime : constant Integer := 1;
        period : constant Integer := 2;
        computingTime : constant Integer := 1;
        startingTime : Time;
    end task_t;
end pkg_task;

When I compile I obtain the error mentioned on the title in all the lines of the task specification where I declare the variables, and I don't know what is the problem.

Jacob Sparre Andersen · Answer 1 · 2018-04-30T17:27:58.070

3

The interface to a task is its entries, so you only declare entries in a task specification. Any local variables in a task are declared in the declarative part of the task body.

A task without any entries is simply declared:

task Something;

edited Apr 30 '18 at 17:27

answered Apr 30 '18 at 15:06

Jacob Sparre Andersen

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And what if I have no entries on the task? – thmasker Apr 30 '18 at 15:10
You then just have a body in which you declare your variables, just have a look at https://en.wikibooks.org/wiki/Ada_Programming/Tasking#Tasks – Frédéric Praca Apr 30 '18 at 15:11
Do I need anyway the .ads file? because when I compile it gives me an error if it does not exist – thmasker Apr 30 '18 at 15:13
@thmasker actually, it is rather the other way around : you cannot have a body that is not needed (by its spec, or as a "main"). – Faibbus Apr 30 '18 at 16:07
Packages always need a specification, even if it is empty. – Jacob Sparre Andersen Apr 30 '18 at 17:28
If a package specification doesn't obviously require a package body, it is not allowed to have one. - But you can force a package to need a body by putting the pragma `Elaborate_Body` in the package specification. – Jacob Sparre Andersen Apr 30 '18 at 17:30

score 2 · Accepted Answer · edited Apr 30 '18 at 17:32

2

As Jacob wrote, you can't export anything that is not an entry in tasks. In this case, your task is really straightforward

package pkg_task is
   task type task_t;
end pkg_task;

In the body, you can then use your variables.

package body pkg_task is

   task body task_t is
      Activation_Time : constant Integer := 1;
      Period          : constant Integer := 2;
      Computing_Time  : constant Integer := 1;
      -- Starting_Time   : Time;
   begin
      null;
   end task_t;
end pkg_task;

Anyway, it would be easier if you explained us what you're trying to do.

edited Apr 30 '18 at 17:32

Jacob Sparre Andersen

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answered Apr 30 '18 at 15:22

Frédéric Praca

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That was it. You both solved my problem. I was just trying to do the packgage specification with no entries. – thmasker Apr 30 '18 at 15:27
Great! I hope you start liking programming in Ada ;) – Frédéric Praca Apr 30 '18 at 15:29

Illegal declaration in task definition

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