Re: Dos Environment varables

["Jeffrey D. Cherry" <jdcherry@utech.net>]

Al,

The GNAT OS_Lib route is a great way to get environment variables when
you want to port your application accross different platforms.  If you
are going to stay with Windows, then using the Win32 API is a good
"portability" alternative, again the condition being that you stay
within the Windows family (95/98/NT).  Here is a function that I've used
with the OA compiler.  I've used it on Windows 95, 98, and NT without
any problems.  Hope it helps.

Regard,
Jeffrey D. Cherry
Logicon Geodynamics

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with Ada.Strings.Unbounded;

function Get_Environment_Variable(Name : in string)
      return Ada.Strings.Unbounded.Unbounded_String;
-----
with Win32;
with Win32.Winbase;

with Ada.Characters.Latin_1;

function Get_Environment_Variable(Name : in string) 
      return Ada.Strings.Unbounded.Unbounded_String is
   
   N : string(1 .. Name'length+1) := Name & Ada.Characters.Latin_1.Nul;
   B : string(1 .. 2048);
   S : Win32.DWORD;
         
begin -- Get_Environment_Variable
   S := Win32.Winbase.GetEnvironmentVariable(Win32.Addr(N),
Win32.Addr(B),
         Win32.DWORD(B'length));
   if (integer(S) <= 0) then
      return Ada.Strings.Unbounded.Null_Unbounded_String;
   else
      return
Ada.Strings.Unbounded.To_Unbounded_String(B(1..positive(S)));
   end if;            
end Get_Environment_Variable;
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