Re: Ada.Storage_IO: applied example?

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

On Wed, 24 Oct 2012 13:51:21 +0200, Yannick Duch�ne (Hibou57) wrote:

> Le Wed, 24 Oct 2012 12:28:00 +0200, Dmitry A. Kazakov  
> <mailbox@dmitry-kazakov.de> a �crit:
> 
>> On Wed, 24 Oct 2012 02:49:02 -0700 (PDT), AdaMagica wrote:
>>
>>> See AARM A.9(1.a):
>>> Reason: This package exists to allow the portable construction of
>>> user-defined direct-access-oriented input-output packages.
>>
>>    portable construction of X /= construction of portable X
>>
>> The package cannot be used to write files in a way that an application
>> compiled by one compiler X1 under OS Y1 could write a file readable for
>> compiler X2 under OS Y2.
>>
>> In order to be portable they should have defined the exact representation
>> of the object in the file. Yes, nobody would do that, but then they  
>> should not include useless packages into the standard either.
> 
> What about private persistent storage?

   X1 = X2 and Y1 = Y2

What are chances of having this? And what are chances that a user would
mistakenly use the package when X1 /= X2 or Y1 /= Y2?

Specifically to persistent storage, you would need to be able to debug it,
reinterpret using some independent tools, have redundancy and additional
checks on top, be able to store indefinite objects, be independent on the
medium etc. A *generic* package parametrized by a private type with no
representation defined is a non-starter.

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