Re: anonymous access type

[Jean-Pierre Rosen <rosen@adalog.fr>]

Maciej Sobczak a �crit :
> Now, being a good citizen, I would like to explicitly stress that the
> parameter is passed 'in' instead of relying on implicit mode, so let's
> add the 'in' keyword where it belongs:
> 
>    procedure Call (Process : in not null access procedure);
> 
> GNAT says: "anonymous access type definition not allowed here".
> 
> I cannot find anything in the standard that would explain this. Any
> references are welcome.
> 
6.1(15/2): if you have an access definition, you can't specify a mode.

Although it is not syntactically specified this way in the RM, you
should see "access" as a kind of mode in itself. Therefore, it replaces
the "in".

The idea (at least in Ada95) was that you did not pass a pointer, you
passed an object (of the designated type) by reference. Thus, "access"
was really the mode. It is a bit less true in 2005, since null values
are now allowed.

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           J-P. Rosen (rosen@adalog.fr)
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