Is 'out' different from 'in out' (Was: Uninitialized "out" parameters)

[gauthier@unilim.fr (Michel Gauthier)]

In article <Duwwqn.AD0@world.std.com>, bobduff@world.std.com (Robert A
Duff) wrote:

>>  In article <gauthier-1907961215520001@164.81.60.62>,
>>  Michel Gauthier <gauthier@unilim.fr> wrote:
>>  >This problem is harmless here, but can lead to counterintuitive
results when
>>  >the type implies initialisation (records, controlled types, access types).
>>  >Intuitively, the actual parameter should be Finalize'd prior to
entering the
>>  >subprogram, and re-Initialize'd as part of elaborating the declarative part
>>  >of the subprogram ___Is it the behaviour that results from LRM ?___
>>  
>>  No.  Controlled types are always passed by reference.  That is, the
>>  formal is a view of the actual (not a copy of it).  So no finalization
>>  takes place on parameter passing.

Reference vs. copy passing does not seem to be relevant here.

My intuitive view, and I guess the easier to teach, is that 'out'
parameters involve
initialization at the beginning of the subprogram. I remember a discussion
during
the 9X process about 'out', and a conclusion that there was no longer a
difference
between 'out' and 'in out'. Of course, I do not assert that all 83 compilers did
behave the intuitive way.

So, I repost the question in another form :
___is there a difference between 'out' and 'in out' parameters ?___

Consequent questions are :
___is an 'out' pointer reset to null when entering the subprogram ?___
___is an 'out' controlled object finalised and reinitialised when entering
the subprogram ?___
___is an 'out' record with initial values reinitialised when entering the
subprogram ?___

Finally, ___an AI discussion might be envisaged___. Don't you think so ?

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