Re: Accessing Windows environment vairables in ObjectADA on windows

["Steve" <nospam_steved94@comcast.net>]

Here is an example that works with ObjectAda 7.2.2:

with ADA.Text_IO;
with Win32;
with Win32.WinBase;
with Interfaces.C;
with Interfaces.C.Strings;

procedure GetEnvVar is
    use type interfaces.c.unsigned_long;
    use type interfaces.c.size_t;
    EnvVar : aliased Interfaces.C.Char_Array := Interfaces.C.To_C(
"TEST_SOURCE_DIR" );
    EnvVal : aliased Interfaces.C.Char_Array(0..99);
    len    : Win32.DWORD;
    last   : Interfaces.C.size_t;
begin
      Len:=100;
      Len:=Win32.WinBase.GetEnvironmentVariable(
              EnvVar(0)'unchecked_access,
              EnvVal(0)'unchecked_access,
              EnvVal'Length);
      if Len > 0 then
         last := Interfaces.C.size_t( Len - 1 );
         Ada.Text_IO.Put_Line( Interfaces.C.To_Ada( EnvVal(0..last) &
Interfaces.C.NUL ) );
      else
         Ada.Text_IO.Put_Line( "Env var not found" );
      end if;
end GetEnvVar;

You'll need to include:
  c:\program files\aonix\objectada\win32ada\binding\lib
In the "Normal" directory links, and:
  c:\program files\aonix\objectada\apilib
In the "Linker only" directory links for this example to work.

Steve
(The Duck)


"TARAN TRIPATHI" <tarantripathi@ieee.org> wrote in message
news:b949b6a7.0410142325.3a379563@posting.google.com...
> Hi All,
>
> This is what I have.
>
> I have a win batch file which sets an environment variable say
> "TEST_SOURCE_DIR"
>
> setlocal
> ..
> set TEST_SOURCE_DIR=%1
> ...
> endlocal
>
> For the purpose of seeing how to do it I used set TEST_SOURCE_DIR=C:\
> on command prompt to set the variable.
>
> I have to access this evironment variable in my ADA code.
> This is test code I wrote:
>
> with ADA.Text_IO,System.RTS.Win32;
> procedure GetEnvVar is
>     EnvVal:String(1..100):=(others=>' ');
>     len:System.RTS.Win32.DWORD:=100;
> begin
>
Len:=System.RTS.Win32.GetEnvironmentVariable("TEST_SOURCE_DIR",EnvVal'Addres
s,Len);
>       Ada.Text_IO.Put_Line(EnvVal);
> end GetEnvVar;
>
> The GetEnvironmentVariable function is defined in System.RTS32.Win32
> packages in Win32INT file.
>
> The problem is that the GetEnvironmentVariable function returns null
> for TEST_SOURCE_DIR but gives the correct value for all other Env
> variables like HOME, ALLUSERSPROFILE,APPDATA, PROCESSOR_ARCHITECTURE
> etc, but never for TEST_SOURCE_DIR.
>
> Also the funnier thing is that if I donot catch the return value of
> GetEnvironmentVariable funtion and use it as such
>
System.RTS.Win32.GetEnvironmentVariable("TEST_SOURCE_DIR",EnvVal'Address,Len
);
> I get a compiler error
> " Error: line 34 col 19 LRM:5.1(4), Procedure call, entry call, or
> code statement expected, Continuing "
> which relates to BNF for simple statement. I believe we need not
> necessarily capture the return value of any function(?)
>
> Does the variable being local or system variable make any difference?
>
> I googled many a times for this but no help. I've looked around at
> FAQ's and the
> adahome reference pages, but I haven't found anything.
> I an using ObjectAda 7.2 on Windows NT.
>
> I'm not supposed to use florist package or POSIX/ADA interface. Even a
> C library is not assured so that I can use #pragma
> Interface(C,getenv).
> I have to use the GetEnvironmentVariable function.
>
> Any help or pointers would be appreciated.
> Thanx in advance.
>
> Regards,
> Taran.