From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on
	ip-172-31-74-118.ec2.internal
X-Spam-Level: 
X-Spam-Status: No, score=-0.9 required=3.0 tests=BAYES_00,FORGED_GMAIL_RCVD,
	FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.5-pre1
Path: eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: =?UTF-8?Q?Bj=c3=b6rn_Lundin?= <b.f.lundin@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: converting pointer to value
Date: Fri, 5 Mar 2021 09:54:09 +0100
Organization: A noiseless patient Spider
Message-ID: <s1srjh$8hu$1@dont-email.me>
References: <s1r05i$d1$1@dont-email.me>
 <02709d96-50fe-4e87-bdb5-4f430fa2717an@googlegroups.com>
 <s1r5o1$5df$1@gioia.aioe.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Date: Fri, 5 Mar 2021 08:54:09 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="c9e3b2236f724ff4b8eeba0adbb7f865";
	logging-data="8766"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19Wxl708Uy5HQ1vj6cKqDq6"
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:78.0)
 Gecko/20100101 Thunderbird/78.6.1
Cancel-Lock: sha1:+60dVe7ldlnsV454HPWuiPJFFVQ=
In-Reply-To: <s1r5o1$5df$1@gioia.aioe.org>
Content-Language: sv
Xref: reader02.eternal-september.org comp.lang.ada:61478
List-Id: <comp.lang.ada>

Den 2021-03-04 kl. 18:35, skrev Dmitry A. Kazakov:

> You need not to know that:
> 
>     declare
>        P : SQLPOINTER := ...;
>        A : System.Address;
>        pragma Import (Ada, A);
>        for A'Address use P'Address;
>        T : My_Fancy_Object;
>        pragma Import (Ada, My_Fancy_Object);
>        for T'Address use A;
>     begin
>        ... -- Use T at P
> 


I did try this
procedure Exec (Statement_Handle : in Sqlhstmt) is
     RC :  SQLRETURN := SQLExecute (Statement_Handle);
     Pvalue : aliased Sqlpointer;
     Sent: Integer := 0;
     Datalen : Integer := 14;
     Buffer  : String  (1..10) := (others => ' ');
     S_Ptr   : Ptr_String;
     Sa      : aliased system.Address;
     type Ia is access all SQLINTEGER;
     Psa : Ia;
    begin
       Text_Io.Put_Line ("Exec: " & Rc'Img);
     --test for unset clob
       Rc := Sqlparamdata (Statement_Handle,Pvalue'Access);
       Text_Io.Put_Line ("SQLParamData1: " & Rc'Img );
       Sa := to_Address(Pvalue);
       declare
         I : SQLINTEGER ;
         for I'Address use Sa;
       begin
          Text_Io.Put_Line ("SQLParamData1.2: " & I'Img );
       end;
       if Rc /= Sql_Need_Data then
         return;
       end if;

and as a result I got

SQLParamData1.2:  4790608

(intel 64bit Linux)

I expected 5
Later today I'll try the truick with pragma Import.
However I don't really see/understand the difference.




--
Björn