Expected private type “Ada.Real_Time.Time_Span”

Question

I have the following task body:

with Ada.Text_IO; use Ada.Text_IO;
with Ada.Real_Time; use Ada.Real_Time;
with Ada.Task_Identification; use Ada.Task_Identification;

package body pkg_task is
    task body task_t is
        activationTime : Time_Span := 1; -- 1 second
        period : Time_Span := 2; -- 2000 milliseconds
        computingTime : Time_Span := 1; -- 1000 milliseconds
        activeWaiting : Integer;
        startingTime : Time;
    begin
        delay To_Duration(activationTime);

        startingTime := Clock;

        while (Clock - startingTime) < computingTime loop
            activeWaiting := activeWaiting + 1;

            Put_Line("Task(" & Image(Current_Task) & "): Internal variable: " & Integer'Image(activeWaiting));

            if (period - (Clock - startingTime)) < computingTime then
                delay To_Duration(period - (Clock - startingTime));
            end if;
        end loop;
    end task_t;
end pkg_task;

When compiling, I obtained the mentioned error:

gcc-7 -c pkg_task.adb
pkg_task.adb:8:47: expected private type "Ada.Real_Time.Time_Span"
pkg_task.adb:8:47: found type universal integer
pkg_task.adb:9:39: expected private type "Ada.Real_Time.Time_Span"
pkg_task.adb:9:39: found type universal integer
pkg_task.adb:10:46: expected private type "Ada.Real_Time.Time_Span"
pkg_task.adb:10:46: found type universal integer

The thing is that I am quite new in this language, and I do not understand much about it. In fact I find it a bit complex may I say, and I do not find much information around the Internet.

Answer 1

Since Time_Span is a private type, literals will not be automatically converted. Try:

To_Time_Span (1.0)

Also, since the parameter to To_Time_Span is a real type (a duration), you need the decimal part. Ada won't let you mix integers and real types without explicit conversions.