阿达左手的任务不得限制类型

I am at loss after spending hours on this.

花了好几个小时后,我感到很茫然。

Protected type declaration:

受保护的类型声明:

   protected type AdditionMachine is
      procedure setTask (Item : in WorkerTask);
      procedure getTask (Item : out WorkerTask);
      procedure calculate;
   private
      machineType : String (1 .. 1) := "A";
      job : workerTask;
   end AdditionMachine;

Task:

   task body SimpleTask1 is 
     Available     : Natural := ADDITION_MACHINES;
      Elements      : array (1 .. ADDITION_MACHINES) of AdditionMachine;
   begin
     loop
        select
           when Available > 0 =>
              accept getMachine (machine : out AdditionMachine) do
                  machine := Elements(Available);
                  Available := Available - 1;
              end getMachine;
        or
            accept addMachine (machine : in AdditionMachine) do
                 Available := Available + 1;
                 Elements(Available) := machine;
              end addMachine;
        end select;
     end loop;
   end  SimpleTask1;

At line Elements(Available) := machine; and machine := Elements(Available); I get "left hand of assingment must not be limited type"

在线元素(可用):=机器;和机器:=元素(可用);我得到“左手的assingment一定不能限制类型”

I have no idea how to fix this, I've found nothing when I googled, can anyone help?

我不知道如何解决这个问题,当我用Google搜索时,我什么也没找到,有人可以帮忙吗?

edit: I now know that protected types are limited, but how do I accomplish a pool of protected objects without something like above?

编辑:我现在知道受保护的类型是有限的,但是如何在没有上述内容的情况下完成受保护对象池?

1 个解决方案

#1

From ARM 7.5, Limited Types,

从ARM 7.5,有限类型,

A limited type is (a view of) a type for which copying (such as for an assignment_statement) is not allowed. A nonlimited type is a (view of a) type for which copying is allowed.

限制类型是(视图)不允许复制(例如,对于assignment_statement)的类型。无限制类型是允许复制的(视图a)类型。

However, you are allowed to copy accesses to limited objects.

但是,您可以将访问权限复制到受限对象。

So, if you have declared

所以,如果你已经申报了

protected type AdditionMachine is
   ...
end AdditionMachine;
type AdditionMachine_Access is access AdditionMachine;

you can write something like this (I haven’t tested it):

你可以写这样的东西(我还没有测试过):

task body SimpleTask1 is 
   Available : Natural := ADDITION_MACHINES;
   Elements  : array (1 .. ADDITION_MACHINES) of AdditionMachine_Access
     := (others => new AdditionMachine);
begin

You’ll need to take care of deallocating the allocated objects when you’ve done with them (if the program needs to run indefinitely, anyway). I don’t think there’ll be a problem with protected objects (but what happens if a task is waiting on a PO that you deallocate?), and recent GNATs are OK with deallocating tasks provided the tasks have open terminate alternatives, ARM 9.7.1, or have already terminated - perhaps by being aborted).

当你完成它们时,你需要注意释放已分配的对象(如果程序需要无限期地运行)。我不认为受保护对象会出现问题(但如果任务正在等待您解除分配的PO上会发生什么?),并且最近的GNAT可以解除分配任务,前提是任务具有开放终止替代方案,ARM 9.7 .1,或已经终止 - 也许是通过中止)。

#1