Re: Warning: accessibility check failure with GNAT GPL 2013

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Mon, 28 Oct 2013 08:23:40 -0700 (PDT), sangomarco@gmail.com wrote:

> Thanks for your quick response. I don't have enough experience with Ada,
> please could you tell me more about the rule? I don't understand why this
> is not allow.

It is allowed, unfortunately. That is why you have got only warning, not an
error. Unfortunately, because it does not make sense in 90% of cases in
practice.

> My goal is to create a main task which makes a successor
> tasks if necessarry. And, since I cannot use the sybtype mak to create a
> new task in the current execution of a main task body as the following
> declaration

Use a named access type instead. E.g.

   type Cyclic_Thread_Ptr is access all Cyclic_Thread:

Informally, "new" adapts to the expected access type. So does the anonymous
access type from its side. When both meet each other there is no
information available to determine the scope where the allocated object
would live. The language rules use the most conservative estimation of that
scope (the body of the subprogram), which in practice never corresponds to
the programmer's intent. The resulting accessibility check necessarily
fails at run time. Be glad you were warned by the compiler.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de