From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 border1.nntp.dca1.giganews.com!nntp.giganews.com!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!feeder.erje.net!eu.feeder.erje.net!eternal-september.org!feeder.eternal-september.org!mx02.eternal-september.org!.POSTED!not-for-mail
From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: access-to-classwide has non-static size?
Date: Fri, 27 Mar 2015 08:26:17 +0000
Organization: A noiseless patient Spider
Message-ID: <lyk2y2luc6.fsf@pushface.org>
Mime-Version: 1.0
Content-Type: text/plain
Injection-Info: mx02.eternal-september.org;
 posting-host="e362043f1eec5b72fb571caf32708303";
 logging-data="15912"; mail-complaints-to="abuse@eternal-september.org";
 posting-account="U2FsdGVkX19QF04DqJjafp9Ae2+iZ5lXSOgOz7mqQQ0="
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (darwin)
Cancel-Lock: sha1:7T+SvaPN9ZtJRY8RiIPYWT4iq0k=
 sha1:LOqe2vFoEeqM6Ezq+xQPkw6i7pY=
Xref: number.nntp.giganews.com comp.lang.ada:192584
Date: 2015-03-27T08:26:17+00:00
List-Id: <comp.lang.ada>

I'm creating a PO which has a member which is a bounded vector of
pointer-to-classwide,

   type Event_Base is abstract tagged limited private;
   type Event_P is access all Event_Base'Class;

...

   package Event_Queues is new Ada.Containers.Bounded_Vectors
     (Index_Type   => Positive,
      Element_Type => Event_P);

...

   protected type Dispatchable_Events is
      ...
   private
      ...
      The_Events : Event_Queues.Vector (Capacity => Capacity);

and when compiling with the Ravenscar profile (GNAT GPL 2014, GCC 4.9.1,
GCC 5.0.0 20150208) the compiler says

   warning: component has non-static size
   warning: creation of protected object of type "Dispatchable_Events"
    will violate restriction No_Implicit_Heap_Allocations

Is this (the non-static size part!) right?

I tried declaring Event_P "with Size => 64"; no difference.

I think, studying the output of -gnatR, a pointer-to-classwide is a thin
pointer, i.e. 4 bytes on arm-eabi).