Re: (#pragma data-seg) equivalent in Linux ...

[Dan Kegel <dank at kegel dot com>]

comp sci wrote:
>       Iam really not sure , but I think this is a
> normal memory shared among multiple processes.In QT
> based application(porting from MFC based app) this is
> used in the following way:
>       I have a main window in which I register my
> window handle (save the self referencing pointer) in a
> shared variable.Later Iam starting a new window(sort
> of plugin) using execl and I want this plugin to
> register itself to the main window using the already
> stored main window handle in shared variable.
>       In Windows this scenerio is implemented using
> pragma 

Ah.  Linux (like Unix) uses functions, not pragmas, to
set up shared memory segments.  See e.g. the mmap() function.
But shared memory is not used terribly often for
communicating between GUI apps; there are other options.

The other options range from simple to mind-bogglingly complex.
It might be best to discuss this on the qt user's mailing list.

If you want the ugly details:
Qt itself uses X's  Inter-Client Exchange (ICE) Protocol
(via X's Session Management functions) to implement QSessionManager;
ICE is documented e.g. at http://nscp.upenn.edu/aix4.3html/x11/specs/pdf/ICElib.pdf
but may be too complicated for the average app.
Another document covering how X applications should communicate
(e.g. for cut and paste) is http://tronche.com/gui/x/icccm/
- Dan
--
Dan Kegel
http://www.kegel.com
http://counter.li.org/cgi-bin/runscript/display-person.cgi?user=78045


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