"Integer" value of a CHARACTER

[stachour@sctc.com (Paul Stachour)]

  I have this "simple" problem.  I have something that I need
its internal representation of.  I need this to calculate a
checksum or a hash-value or ...  I really don't even care what
the value is, or plan to do anything neat-o with it.  I just
need it to be repeatable.
  In the (simplified) example below, I am trying to get a hash-value
from several characters in a string.  However, I seem to get problems
in doing this.  In the example given, I get "constraint-error" on the
attempt to do the "conversion". (V_Name is a 60-char string with an
OK name in it, the first character is a "c".)

  What am I doing wrong?  How should I be doing it?
[Unchecked conversion between an 8-bit character and an
integer is not guarenteed either, is it?  Or do I work
with some particular range of integer?]

-- ********************************************************** --
function Hash_Name(
    The_Name                          : in V_Name ) 
  return Positive is
  C:                                    STRING(1..1);
begin
   C(1) := The_Name(1);
   return POSITIVE'VALUE(C(1..1));
--1      return POSITIVE'VALUE(The_Name(1));
end;

-- ********************************************************** --

-- 
Paul Stachour         Secure Computing Technology Corp
stachour@sctc.com      1210 W. County Rd E, Suite 100           
		 	   Arden Hills, MN  55112
                             [1]-(612) 482-7467