Dos Environment varables

Dos Environment varables

[Al Lively]

Can anyone advise how I can access (through Ada code) the contents of local
environmental variables?

Thanks,

Re: Dos Environment varables

[Keith Thompson]

"Al Lively" <al.lively@business.gatech.edu> writes:
> Can anyone advise how I can access (through Ada code) the contents of local
> environmental variables?

As others have pointed out, some Ada compilers provide routines for
this.

If yours doesn't, or if you want your code to be portable across
compilers, you can probably call the standard C getenv() function.
The C declaration is

     char *getenv(const char *name);

See Interfaces.C (section B.3 in the RM) for information on how to
call C functions from Ada.

-- 
Keith Thompson (The_Other_Keith) kst@cts.com  <http://www.ghoti.net/~kst>
San Diego Supercomputer Center  <http://www.sdsc.edu>                 <*>
Techno-geek.  Mouse bigger than phone.  Bites heads off virtual chickens.

Re: Dos Environment varables

[Gautier]

> Can anyone advise how I can access (through Ada code) the contents of local
> environmental variables?

Which compiler, platform ?

With GNAT, you obtain them by the GNAT.OS_lib getenv function.
E.g.

with GNAT.OS_lib;

...

  function Get_env_string(name:String) return String is
    begin
      return GNAT.OS_lib.getenv(name).all;
    end;

-- 
Gautier

--------
http://members.xoom.com/gdemont/

Re: Dos Environment varables

[Al Lively]

I am using ObjectAda 7.1 on a windows 95 platform....

Gautier wrote in message <37458BC1.CC63E63E@Maths.UniNe.CH>...
>> Can anyone advise how I can access (through Ada code) the contents of
local
>> environmental variables?
>
>Which compiler, platform ?
>
>With GNAT, you obtain them by the GNAT.OS_lib getenv function.
>E.g.
>
>with GNAT.OS_lib;
>
>...
>
>  function Get_env_string(name:String) return String is
>    begin
>      return GNAT.OS_lib.getenv(name).all;
>    end;
>
>--
>Gautier
>
>--------
>http://members.xoom.com/gdemont/

Re: Dos Environment varables

[Gautier]

> I am using ObjectAda 7.1 on a windows 95 platform....

Aaaah. Maybe it's a function called "Get_env_string"
- that's the name in use in Alsys Ada, the ancestor of OA.
Possibily in a package called "DOS" or "OS" - see manual!

My example was precisely for "glueing" it from GNAT!

-- 
Gautier

--------
http://members.xoom.com/gdemont/

Re: Dos Environment varables

[Jeffrey D. Cherry]

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

-----
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;
-----

Re: Dos Environment varables

[Pascal Obry]

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Jeffrey D. Cherry <jdcherry@utech.net> a �crit dans le message :
37497064.C4457F71@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.

Yes and the best solution could be POSIX. It is compiler and platforms
independant.

Look at Florist for a UNIX implementation and under my homepage for
a partial (yet very usefull) POSIX for Win32.

Pascal.

--

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Re: Dos Environment varables

[Jeffrey D. Cherry]

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For both Al and Pascal ...

Pascal Obry wrote:
> 
> Yes and the best solution could be POSIX. It is compiler and platforms
> independant.
> 
> Look at Florist for a UNIX implementation and under my homepage for
> a partial (yet very usefull) POSIX for Win32.
> 
> Pascal.
> 

Pascal is quite right.  I've used his Win32POSIX packages successfully
on Windows systems (i.e., 95/98/NT).  I've also used them with ObjectAda
7.1.2a at work and with GNAT 3.11p at home, and have never experienced a
problem.  The POSIX package bodies show how the Win32 API can be used to
implement the POSIX functionality and thus are quite instructive for
those learning the Win32 API.  A great example is demo6 in the
aforementioned Win32POSIX binding.  Is uses the package
POSIX.POSIX_Process_Environment and demonstrates its many services for
dealing with environment variables and strings.

So Al, although the Win32 API is popular, I would suggest that you tuck
my previous example code into a nice bit bucket somewhere and follow the
example shown in the demo6 program.  Pascal rightly points out that
POSIX is a much more portable means of dealing with environment
variables, and other operating system services as well.

Regards,
Jeffrey D. Cherry
Logicon Geodynamics

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Re: Dos Environment varables

[David Botton]

If you are using GNAT see gnat.os_lib

also see:

Ada 95 Binding to CGI (Wheeler)
ftp://ftp.cdrom.com/pub/ada/swcomps/cgi/cgi.html

in the getenv code.

David Botton


Al Lively wrote:
> 
> Can anyone advise how I can access (through Ada code) the contents of local
> environmental variables?
> 
> Thanks,