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: 103376,7be1cfc685fd1ce2,start
X-Google-Attributes: gid103376,public
From: Andrew L Moore {66003} <alm@gbr.msd.ray.com>
Subject: Access types vs. Record types as procedure parameters
Date: 1999/08/19
Message-ID: <37BC4F12.E33D50EE@gbr.msd.ray.com>#1/1
X-Deja-AN: 514801053
Content-Transfer-Encoding: 7bit
X-Accept-Language: en
Content-Type: text/plain; charset=us-ascii
X-Complaints-To: usenet@swl.msd.ray.com
X-Trace: swlmail.msd.ray.com 935087891 11374 138.127.37.14 (19 Aug 1999
 18:38:11 GMT)
Organization: Raytheon Company
Mime-Version: 1.0
NNTP-Posting-Date: 19 Aug 1999 18:38:11 GMT
Newsgroups: comp.lang.ada
Date: 1999-08-19T18:38:11+00:00
List-Id: <comp.lang.ada>

I am debating on whether to pass a record object to a procedure or an access type to that record object.

For example I have:

     package body X is
     type Record_Type;
     type Array_Type is array (1 .. n) of Record_Type;
     Array_Object : Array_Type;
     procedure One;
     procedure Two (Parameter : in Record_Type);
     ---More procedures and functions
     end X;
     procedure One is
     begin
     for I in range 1 .. n loop
           procedure Two(Parameter => Array_Object (I));
     end loop;
     end One;
     --------------------------------------------------------------------------------------
     OR:
     package body X is
     type Record_Type;
     type Array_Type is array(1 .. n) of Record_Type;
     type Access_Type is access Record_Type;
      Array_Object : Array_Type;
     function Address_To_Pointer is new
Ada.Unchecked_Conversion(System.Address, Access_Type);
     procedure One;
     procedure Two (Parameter : in Access_Type);
     --More procedures and functions
     end X;
     procedure One is
     Object_Ptr : Access_Type := null;
     begin
     for I in range 1 .. n loop

         Object_Ptr := Address_To_Pointer(Array_Object(I)'Address)
          procedure Two (Parameter => Object_Ptr);
     end loop;
     end One;

I am looking for the way that would provide the greatest speed of
execution.  I know that passing a pointer to an object of a record type
is more efficient that passing the record itself, but would that be
negated by repeated calls to Unchecked_Conversion.  Basically, are there
any advantages to using Unchecked_Conversion to get an access value to
an object to then pass it to a procedure.

Any assistance you could provide would be greatly appreciated.