Re: GNAT for MS Visual Studio

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

On Sat, 06 Oct 2007 17:03:44 +0200, Pascal Obry wrote:

> Matthew Heaney a ļæ½crit :

>> No, this is incorrect.  The container keeps track of nested calls
>> (e.g. Query_Element, Iterate) using a count, in order to prevent
>> container misuse (e.g. deleting the element while it's being
>> queried).  So even though the logical view of the container doesn't
>> change, then physical view does change, and so the standard requires
>> that multiple tasks accessing a container must be properly
>> synchronized, even when the access is read-only.
> 
> Outch! Big mistake to require this to me :(

Why? The container type is not protected, thus you cannot expect it
functioning as if it were the latter.

BTW, I guess if placing a container into a protected object and accessing
it from a function of, might be erroneous on a multi-core platform. Here
two permissions collide: a protected object function can share, the
object's container component cannot. The compiler should change the
implementation of either. Would it?

> Maybe something like "Donļæ½t let best be enemy of good" !

It is rather "We didn't want to change the language to much," like by
making protected types tagged, by introducing pure functions, by allowing
in-out function parameters. It was not the best, not even good...

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