Setting Environment Variables

Setting Environment Variables

[John Lee]

How does one set an environment variable in Ada?  Is there an Ada system
function or must I interface with the C setenv function?  Thanks.

John Lee


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Re: Setting Environment Variables

[Gisle S�lensminde]

In article <8f6h8h$5ee$1@nnrp1.deja.com>, John Lee wrote:
>How does one set an environment variable in Ada?  Is there an Ada system
>function or must I interface with the C setenv function?  Thanks.

You must import it from the OS, it's not available in standard Ada.

By the way, the setenv function is a part of the OS, not C, but yes, 
it has has C linker conventions and is most likely implemented in C. 

--
Gisle S�lensminde ( gisle@ii.uib.no )   

ln -s /dev/null ~/.netscape/cookies

Re: Setting Environment Variables

[Larry Kilgallen]

In article <8f6h8h$5ee$1@nnrp1.deja.com>, John Lee <lee@orion-sim.com> writes:
> How does one set an environment variable in Ada?  Is there an Ada system
> function or must I interface with the C setenv function?  Thanks.

On Alpha VMS you would call STARLET.SETENV to change a console
environment variable, but most likely that is not what you had
in mind.  The notion of "environment variables" is tied to the
operating system you use, and for VMS the C language construct
can be either a logical name or a DCL symbol, as I recall.

The bottom line is, for operating system specific discussions
you really need to specify your operating system in order to
get the answer you want.

Re: Setting Environment Variables

[David Emery]

This is specified in POSIX/Ada, since it's really an OS operation.

         dave

Re: Setting Environment Variables

[Samuel T. Harris]

David Emery wrote:
> 
> This is specified in POSIX/Ada, since it's really an OS operation.
> 
>          dave

So are command-line arguments but they are supported
directly in Ada 95. I find this "its an OS operation"
line of reasoning dubious. Ada.Command_Line specifies
what happens when an implementation has no command-line,
so why not have an Ada.Environment as well?!!!

But since we don't, POSIX is the next best thing.

-- 
Samuel T. Harris, Principal Engineer
Raytheon, Aerospace Engineering Services
"If you can make it, We can fake it!"

Re: Setting Environment Variables

[David C. Hoos, Sr.]

Samuel T. Harris <samuel_t_harris@Raytheon.com> wrote in message
news:391C43C9.5F7DA9E3@Raytheon.com...
> David Emery wrote:
> >
> > This is specified in POSIX/Ada, since it's really an OS operation.
> >
> >          dave
>
> So are command-line arguments but they are supported
> directly in Ada 95. I find this "its an OS operation"
> line of reasoning dubious. Ada.Command_Line specifies
> what happens when an implementation has no command-line,
> so why not have an Ada.Environment as well?!!!
>
Well, reading the existing environment could, of course, be
easily done.  But... setting an environment variable often
requires enlarging the environment space -- meaning copying
the old stuff plus the modification, and deallocating the old, etc.
Some flavors of UNIX don't (or at least didn't 8 years ago) support
setenv, and I remember that VADS was seriously broken on at
least one platform, at that time with an Ada procedure for Setenv.