Re: system call

[Adam Beneschan <adam@irvine.com>]

On Aug 15, 8:40 am, Adam Beneschan <a...@irvine.com> wrote:
> On Aug 13, 11:43 am, "philippe.tor...@free.fr"
>
>
>
>
>
> <philippe.tor...@free.fr> wrote:
> > Hello,
>
> > I have a program, the time of his execution, constructed images, in fact
> > files in PPM (P3, plain text mode)
> > In short, the program does not deal with the viewing of these images
> > (failing to find a library to do ...)
>
> > So I want to entrust this task to an external application (imview,
> > xview, qiv ... etc):
>
> > res = system ("imview out.ppm");
>
> > But each time this code is a new process
> > image viewer (here imview) that arises.
>
> > My application is waiting while I close imview to move to
> > the next iteration.
>
> > Well, now you have guessed the question for each passage on the line above,
> > I would like the external program (imview, qiv, xview ... whatever), load a new image
>
> > Regards!
>
> I'm not real clear on what you're trying to do.  But it sounds like
> you want to run imview or some other program once, and have your
> program tell that program to display a new image whenever it wants to
> display something new.  In order for that to work, the image displayer
> has to be set up to accept that kind of communication.
>
> However, if by "imview" you mean the program documented athttp://hugues.zahlt.info/software_imview.html, that program appears to
> have a server mode.  So you'll need to run it in server mode and then
> communicate with it via a TCP/IP socket.  The documentation should
> explain how to do this, but I haven't looked over it carefully.

Oh, yeah, one other thing: if you do this, you won't be able to use
system("...") to run imview, because "system" will wait for imview to
finish, which will never happen.  You'll need to find a way to spawn
imview without having your application wait for it to finish.  There
are ways to do this on both Unix/Linux and Windows (you don't say what
OS you're using); I think there are probably GNAT library operations
to perform that kind of spawning, but someone who's more knowledgeable
about GNAT than I am will need to help you with those, if you're using
GNAT.  There's no Ada language-defined operations for this.

                                -- Adam