Ada Pointer Size Problem

[aschwarz@acm.org (skidmarks)]

I have a problem with the test program below. Perhaps someone can help me.

1. P1_Size gives an error. P2_Size and P3_Size don't. 
   I would have expected errors everywhere or nowhere.
   I don't understand what is 'non-static' about the
   expression since a typedef is invariant.

2. 'thang' (L13) is erroneous but 'Variable' (L17) is
   not. I suspect that this means that the non-static
   nature of the expression is OK as a statement but
   not in a definition.

3. The string pointer size (eliding the error statements)
   is 64-bits. I am using an AMD 2100 (32-bit) computer
   and gcc-3.3.3-3. I would have expected a 32-bit
   pointer. 

4. The integer pointer size (eliding the error statements)
   is 32-bits. I would have expected that it would be the
   same size as the string pointer.

I've looked at the 'info' tex file included with the 
gcc distribution and so far have not found how to 
change a 64-bit pointer to a 32-bit pointer. I've
thought that maybe I am getting the dope vector size
associated with the String_Ptr but this really doesn't
make sense. The Integer_Ptr is only 32-bits which 
seems to be correct but both pointers should be the 
same.

Any idea of what I'm really missing?

art


--------------------------------------------------------

# compiling under Cygwin on a Windows 2000, AMD 2100 CPU
#  gcc-3.3.3-3

>> gcc -c -gnatfv -gnatl junk.adb

GNAT 3.3.3 (cygwin special)
Copyright 1992-2002 Free Software Foundation, Inc.

Compiling: junk.adb (source file time stamp: 2004-10-10 19:50:18)

     1. with Text_IO; use Text_IO;
     2.
     3. procedure junk is
     4.    type String_Ptr  is access all String;
     5.    type Integer_Ptr is access all Integer;
     6.
     7.    In_Size  : constant         := Integer'Size;
     8.    Fl_Size  : constant         := Float'Size;
     9.    P1_Size  : constant         := String_Ptr'Size;
                                                    |
        >>> non-static expression used in number declaration

    10.    P2_Size  : Integer          := String_Ptr'Size;
    11.    P3_Size  : constant Integer := String_Ptr'Size;
    12.    thing    : constant         := Integer'Max(In_Size, Fl_Size);
    13.    thang    : constant         := Integer'Max(thing, P2_Size);
                                                 |
        >>> non-static expression used in number declaration

    14.    Variable : Integer;
    15.
    16. begin -- junk
    17.    Variable         := Integer'Max(In_size, String_Ptr'Size);
    18.    Put_Line("Integer = " & Integer'Image(Integer'Size) );     -- 32 bits
    19.    Put_Line("Float   = " & Integer'Image(Float'Size)   );     -- 32 bits
    20.    Put_Line("Int_Ptr = " & Integer'Image(Integer_Ptr'Size));  -- 32 bits
    21.    Put_Line("Ptr     = " & Integer'Image(String_Ptr'Size));   -- 64 bits
    22.    Put_Line("Ptr1    = " & Integer'Image(P1_Size));           -- 64 bits
    23.    Put_Line("Ptr2    = " & Integer'Image(P2_Size));           -- 64 bits
    24.    Put_Line("Ptr3    = " & Integer'Image(P3_Size));           -- 64 bits
    25.    Put_Line("Variable= " & Integer'Image(Variable));          -- 64 bits
    26. end junk;

 26 lines: 2 errors
>>