Quick Protected Object question

Quick Protected Object question

[markp]

I have a very quick protected object question. In a standard proected
object setup as follows:

protected Test is
   procedure A;
   procedure B;
private
   Z : integer := 0;
end Test;

protected body Test is
   procedure A is
   begin
      < set of statements>
   end A;

   procedure B is
   begin
      < set of statements>
   end B;
end Test;

The question is this: when procedure A is called, are all threads that
try to call B suspended until A finishes or, do the threads that call
B execute as long as A is not touching the private data "Z". Is the
lock at the procedure level or only at the data level?

Thank you.

Re: Quick Protected Object question

[Ludovic Brenta]

On Dec 8, 2:34 pm, markp <markwor...@yahoo.com> wrote:
> I have a very quick protected object question. In a standard proected
> object setup as follows:
>
> protected Test is
>    procedure A;
>    procedure B;
> private
>    Z : integer := 0;
> end Test;
>
> protected body Test is
>    procedure A is
>    begin
>       < set of statements>
>    end A;
>
>    procedure B is
>    begin
>       < set of statements>
>    end B;
> end Test;
>
> The question is this: when procedure A is called, are all threads that
> try to call B suspended until A finishes or, do the threads that call
> B execute as long as A is not touching the private data "Z". Is the
> lock at the procedure level or only at the data level?

At the procedure level; see ARM 9.5.1 at http://www.adaic.com/standards/05rm/html/RM-9-5-1.html

--
Ludovic Brenta.

Re: Quick Protected Object question

[micronian2]

On Dec 8, 5:43 am, Ludovic Brenta <ludo...@ludovic-brenta.org> wrote:
> On Dec 8, 2:34 pm, markp <markwor...@yahoo.com> wrote:
>
>
>
> > I have a very quick protected object question. In a standard proected
> > object setup as follows:
>
> > protected Test is
> >    procedure A;
> >    procedure B;
> > private
> >    Z : integer := 0;
> > end Test;
>
> > protected body Test is
> >    procedure A is
> >    begin
> >       < set of statements>
> >    end A;
>
> >    procedure B is
> >    begin
> >       < set of statements>
> >    end B;
> > end Test;
>
> > The question is this: when procedure A is called, are all threads that
> > try to call B suspended until A finishes or, do the threads that call
> > B execute as long as A is not touching the private data "Z". Is the
> > lock at the procedure level or only at the data level?
>
> At the procedure level; see ARM 9.5.1 athttp://www.adaic.com/standards/05rm/html/RM-9-5-1.html
>
> --
> Ludovic Brenta.

Hi,

In addition to the reference that Ludovic provided, here is a link
that describes the Eggshell model that is used for protected objects:

http://www.iuma.ulpgc.es/users/jmiranda/gnat-rts/node25.htm

--Micronian Coder