From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,42a57c8ee023f14d
X-Google-Attributes: gid103376,public
From: Hannes Haug <Hannes.Haug@Student.Uni-Tuebingen.de>
Subject: Re: Q: memory management
Date: 1996/06/20
Message-ID: <uvvpw6u79mx.fsf@chaq.informatik.uni-tuebingen.de>#1/1
X-Deja-AN: 161218781
sender: haugha@chaq.informatik.uni-tuebingen.de
references: <9606192037.AA13484@most>
organization: Uni Tuebingen
newsgroups: comp.lang.ada
Date: 1996-06-20T00:00:00+00:00
List-Id: <comp.lang.ada>


>>>>> "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