Hi all,

I am getting this error from GNAT and it is puzzling me a
bit.

Can't we use this attribute to set up a record as big/little
endian as needed?  If I was transferring data from a big
endian machine to a little endian machine wouldn't this
attribute help me from do data marshalling?

Thanks,
Chris Sparks



Compiling: t.adb (source file time stamp: 1998-10-16 09:39:25)

     1.    with Ada.Text_Io; use Ada.Text_IO;
     2.    with Ada.Integer_Text_IO;
     3.    use Ada.Integer_Text_IO;
     4.    with System;
     5.
     6.    procedure T is
     7.
     8.       type Byte is mod 2 **  8;
     9.       type Word is mod 2 ** 16;
    10.
    11.       type Big_Endian is record
    12.             A : Byte;
    13.             B : Word;
    14.             C : Byte;
    15.          end record;
    16.       for Big_Endian use record
    17.          A at 0 range  0 ..  7;
    18.          B at 0 range  8 .. 23;
    19.          C at 0 range 24 .. 31;
    20.       end record;
    21.       for Big_Endian'Bit_Order use System.High_Order_First;
                                                 |
        >>> unsupported value for Bit_Order

    22.
    23.       type Little_Endian is record
    24.             A : Byte;
    25.             B : Word;
    26.             C : Byte;
    27.          end record;
    28.       for Little_Endian use record
    29.          A at 0 range  0 ..  7;
    30.          B at 0 range  8 .. 23;
    31.          C at 0 range 24 .. 31;
    32.       end record;
    33.       for Little_Endian'Bit_Order use System.Low_Order_First;
    34.
    35.       BE : Big_Endian    := (10, 20, 30);
    36.       LE : Little_Endian := (10, 20, 30);
    37.
    38.       BE_Int : Integer;
    39.       for BE_Int'address use BE'address;
    40.
    41.       LE_Int : Integer;
    42.       for LE_Int'address use LE'address;
    43.
    44.    begin
    45.       Default_Base := 2;
    46.
    47.       Put_Line ("BO => " & System.Bit_Order'Image (System.Default_Bit_Order));
    48.       Put ("BE =>"); Put (BE_Int); New_Line;
    49.       Put ("LE =>"); Put (LE_Int); New_Line;
    50.
    51.    end T;