[Qt-interest] Question regarding plugins

[Jason H]

It shouldn't matter much.

Your app know A's interface. 
Your app loads plugnins comforming to A's interface
Your plugin A knows the interface for B, and loads the plugins for it.
Done.

Whether your plugin loader is an app or another plugin doesn't matter.



----- Original Message ----
From: Anatoly Burakov <burakov.anatoly at googlemail.com>
To: Jason H <scorp1us at yahoo.com>
Sent: Tuesday, October 6, 2009 5:32:17 PM
Subject: Re: [Qt-interest] Question regarding plugins

Jason H wrote:
> You have to develop an interface, which is a pure virtual class, so your apps need to have some idea of wht kind of functionality to expect.
>
> You can abstract it further and provide a IUknown style interface, but your complexity will go up. Each plugin should implement one or more instances complying to an interface. You can have several interfaces supported, but you'll have to distinguesh the DLLs that implement one class in some way. 
>
>
>
>
>
> ----- Original Message ----
> From: Anatoly Burakov <burakov.anatoly at googlemail.com>
> To: qt-interest at trolltech.com
> Sent: Tuesday, October 6, 2009 3:37:53 PM
> Subject: [Qt-interest] Question regarding plugins
>
> Hi all
>
> I'm not sure if this is a QT-specific question (more of a general
> programming one). But, anyway.
>
> I am going to build an application which is able to use plugins to
> extend its functionality. Let's say it's a business application, and
> let's say one of the plugins provides application with current currency
> rates. How can other plugins see that information, given the initial
> application should have no idea about currency rates?
>
> I mean - a currency rate is just a variable. What i am asking for is to
> be able to access this variable from within another plugin. Is it
> possible? My guess is that this implies dependency of one plugin on
> another, but i am not sure how can i get exactly that variable (and not
> some newly generated via initializing function of a plugin). So, how can
> i achieve that? Just general guidelines is all i need, i'll figure out
> implementation on my own.
>
> Thanks in advance
Thank you for the reply, but you didn't answer my question on how to
access a variable inside one plugin instance from within another,
different plugin...


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