Re: Q: memory management

[Hannes Haug <Hannes.Haug@Student.Uni-Tuebingen.de>]

>>>>> "Wes" == "W Wesley Groleau (Wes)" <wwgrol@PSESERV3.FW.HAC.COM> writes:

    Wes> :>      subtype Alloc_Buffer is String(1..Num_Chars);
    Wes> :>      type Space_Ptr is access all Alloc_Buffer;
    Wes> :>    ...
    Wes> :>
    Wes> :>      X : Space_Ptr := new Alloc_Buffer;
    Wes> :>    ...
    Wes> :>      Pass_To_Assembler(X.all'Address);

    Wes> Please note that whether you have bounds or not, you do not
    Wes> want to pass the actual pointer to assembler or C or ...

    Wes> An Ada access type is a bit pattern that can be used by code
    Wes> from the same compiler to access the item.  It does not have
    Wes> to be an address, though in most implementations it is.  It
    Wes> also does not have to be the address of the actual item, and
    Wes> in most implementations an access to an unconstrained type is
    Wes> NOT the address of the item.  Mr. Taft's example above is the
    Wes> correct way to let code from another compiler or language get
    Wes> the address of your object.  NOT unchecked conversion from
    Wes> the access type to address.  For some reason, I keep seeing
    Wes> even experienced Ada programmers use the latter (incorrect)
    Wes> method.

And if I use unconstrained arrays ? I think I'd have to pass the address
of the first element. Something like this:

  Pass_To_Assembler(X(X.all'First)'Address)


Well, I think it's time to write a Hello World. Thank you all for the help.

 - hannes