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From: rlove@neosoft.com (Robert B. Love )
Subject: Which compiler is correct??
Date: 1996/09/10
Message-ID: <514uuu$d8i@uuneo.neosoft.com>#1/1
X-Deja-AN: 179819801
organization: NeoSoft, Inc.  
newsgroups: comp.lang.ada
Date: 1996-09-10T00:00:00+00:00
List-Id: <comp.lang.ada>



I've got a situation where I put the same piece of code thru two
compilers on the same hardware and one will compile it, the other
gives errors.  The code is listed below and is taken from Richard
Riehle's article in JOOP on "Managing Runtime Faults".  GNAT compiles
it fine.  Aacademic ObjectAda fails to compile it.

I can see maybe 4 choices:  1)  GNAT is wrong, 2) ObjectAda is
wrong, 3) the code is wrong, 4) I need to set some compile
switches on one compiler or the other.

On a PC with GNAT 304a touted as being compiled for Windows and
GNAT 301 on a NeXT/M68040 I get no errors.

With Academic ObjectAda v7.0.171 I get 3 occurrences of the same error
along with line and column numbers.
  
      LRM:6.4.15(5) If the mode is IN OUT or OUT, the actual
      shall be a name that denotes a variable.

I need a language lawyer to tell me what is actually wrong.

Note I made 2 change to Riehle's article, commented with "my change"


with ada.exceptions; use ada.exceptions;
with text_io,ada.integer_text_io;use text_io;

procedure exception_demo is
   error_list: array(1..3) of exception_occurrence;
   d1,d2,d3: integer;

   function square(data:integer) return integer is
   begin
      return data*data;
   exception
      when error_in_square_function:
        constraint_error => ada.exceptions.save_occurrence
          (error_in_square_function,error_list(1));
        return 0;
   end square;

   function compute(v1,v2:integer) return integer is
   begin
      return square(v1) + square(v2);
   exception
      when error_in_compute:
        constraint_error=>ada.exceptions.save_occurrence
          (error_in_compute,error_list(2));
        return 0; -- my change
   end compute;

begin
   Ada.Integer_Text_Io.Get(Item=>D1);
   Ada.Integer_Text_Io.Get(Item=>D2);
   D3 := Compute(V1=>D1,V2=>D2);  -- my chanage
exception
   when Error_In_Demo:
     others => Ada.Exceptions.Save_Occurrence
       (Error_In_Demo,Error_List(3));
     for I in Error_List'Range loop
        Text_Io.Put_Line(Exception_Message(Error_List(I)));
        Text_Io.Put_Line(Exception_Name(Error_List(I)));
        Text_Io.Put_Line(Exception_Information(Error_List(I)));
     end loop;
end exception_demo;



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