预期的专用类型 "Ada.Real_Time.Time_Span"

Question

我有以下任务正文：

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;

编译时，我得到了提到的错误：

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

问题是我对这种语言很陌生，我对它了解不多。事实上，我可以说它有点复杂，而且我在互联网上找不到太多信息。

Answer 1

由于 Time_Span 是私有类型，因此不会自动转换文本。尝试：

To_Time_Span (1.0)

此外，由于要To_Time_Span的参数是实数类型(持续时间(，因此需要小数部分。 Ada 不允许在没有显式转换的情况下混合整数和实数类型。