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=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM
	autolearn=ham autolearn_force=no version=3.4.4
X-Google-Thread: 103376,3869f0598191b11d
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news2.google.com!news.maxwell.syr.edu!wns13feed!worldnet.att.net!attbi_s51.POSTED!53ab2750!not-for-mail
From: "Steve" <nospam_steved94@comcast.net>
Newsgroups: comp.lang.ada
References: <cdfu3s$k1a$1@e3k.asi.ansaldo.it>
Subject: Re: Porting ADA source
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2800.1437
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441
Message-ID: <waQKc.96454$WX.26098@attbi_s51>
NNTP-Posting-Host: 24.21.42.251
X-Complaints-To: abuse@comcast.net
X-Trace: attbi_s51 1090244380 24.21.42.251 (Mon, 19 Jul 2004 13:39:40 GMT)
NNTP-Posting-Date: Mon, 19 Jul 2004 13:39:40 GMT
Organization: Comcast Online
Date: Mon, 19 Jul 2004 13:39:40 GMT
Xref: g2news1.google.com comp.lang.ada:2237
Date: 2004-07-19T13:39:40+00:00
List-Id: <comp.lang.ada>

"Giacomo Polizzi" <mio@.mio> wrote in message
news:cdfu3s$k1a$1@e3k.asi.ansaldo.it...
> Hello,
>
> I have to port an ADA program from an Unix DEC Alpha machine with a DEC
ADA
> compiler to a Linux pc machine with gnat (gcc) compiler.
>
> The task is to have, if possible, an unique source code compilable on both
> platforms but there are the following problems:
>
> 1) some system packages that execute the same kind of operations have
> different names in the two compilers
>
> 2) some system functions (for example mathematical function) have
different
> names in the two compilers

Have you considered obtaining GNAT for DEC Alpha Unix?  This may resolve
the different names issue.

>
> 3) the word length is 64 bits on DEC Alpha and 32 bits on pc so it is not
> always possible to use the same standard type (for example the long type
is
> 64 bits on Alpha and 32 bits on pc)
>
> 4) the standard type (long long) used by gcc on pc to solve the previous
> problem is not supported by the DEC ADA compiler

The basic answer here is: don't use the standard types.  Define your own
or use the definitions in the Interfaces package.  If you have a large base
or code using the predefined types, look for a tool to convert these to
your own definitions.

> 5) the different word length modifies some structure length used to define
> interface messages with other external programs
>

Use representation clauses to explicitly define structure layout the same on
both systems.

> Is there something like #IFDEF of C language that I can use in ADA ?
>
I believe GNAT has a pre-processor you could use, but I have never used it.

Steve
(The Duck)

> Is there any other kind of solution for the above problems ?
>
> Thanks to everybody
>
> Giacomo
>
>