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From: gisle@spurv.ii.uib.no (Gisle S�lensminde)
Subject: Re: ada to c interfaces and CHARS_PTR
Date: 2000/03/09
Message-ID: <slrn8cg0rv.mlp.gisle@spurv.ii.uib.no>#1/1
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References: <38C7E515.29C42580@mindspring.com>
Organization: University of Bergen, Norway
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Newsgroups: comp.lang.ada
Date: 2000-03-09T00:00:00+00:00
List-Id: <comp.lang.ada>

In article <38C7E515.29C42580@mindspring.com>, Al Johnston wrote:
>I have been trying (for longer than I care to admit) to use the
>following c subroutine from
>ada:

C has not 'in out' parameters, only 'in' parameters. To pass the 
pointer to the string you can use system'address. str'address is
equivalent to &str in C. The following Ada code can replace 
the Ada code of your last posting:

with text_io;
with interfaces.c.strings;
with System;
use  interfaces.c.strings;

package body a_sub is

procedure a_sub is

   procedure c_sub(in_strg_fml    : CHARS_PTR;
                   inout_strg_fml : System.address);
   pragma import(c,c_sub,"sub");

   in_strg_act    : CHARS_PTR;
   inout_strg_act : CHARS_PTR := Null_Ptr;

begin
   text_io.put_line("  in  a_sub");

   in_strg_act := NEW_STRING("I am here");


   c_sub(in_strg_act, Inout_Strg_Act'address);

   text_io.put_line("----------");
   text_io.put_line("He said ==>> "
                    & VALUE(inout_strg_act) &
                    " <<==");
   text_io.put_line("  out a_sub");
end a_sub;

end a_sub;





--
Gisle S�lensminde ( gisle@ii.uib.no )   

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