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From: =?ISO-8859-1?Q?Hibou57_=28Yannick_Duch=EAne=29?=
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Subject: Re: Private or public task ?
Date: Fri, 5 Feb 2010 18:20:58 -0800 (PST)
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On 5 f=E9v, 22:38, "Jeffrey R. Carter" <spam.jrcarter....@spam.acm.org>
wrote:
> Technically this is a bounded error: Ada.Text_IO.Put* operations are pote=
ntially
> blocking, and should not be called from a protected operation.

On 5 f=E9v, 22:40, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> This is illegal, because protected procedure shall not perform potentiall=
y
> blocking actions (like I/O.

Here is the reference (for any other peoples who read this thread) :
First occurrence of this requirement appears as an example in [ARM
9.5(4.e)] :

procedure Op2 is
  begin
    Op1; -- An internal call.
    Pt.Op1; -- Another internal call.
    PO.Op1; -- An external call. It the current instance is PO, then
            -- this is a bounded error (see 9.5.1).
    Other_Object.Some_Op; -- An external call.
  end Op2;

Then formally stated at [ARM 9.5.1(8)] :
=93 During a protected action, it is a bounded error to invoke an
operation that is potentially blocking. =94 (follows a list of
operations defined to be potentially blocking)
And later in [ARM 9.5.1(17)] :
=93 If the bounded error is detected, Program_Error is raised. If not
detected, the bounded error might result in deadlock or a (nested)
protected action on the same target object. =94

So it is not guaranteed to be a bounded error, as nested protected
action may succeed.

By as soon as it is said it is a potential error, ... all is said.