Access Qt plugin classes from other plugins

Joshua195

Hi, I am loading a few shared object plugins using QPluginLoader from some subdirs:

myInterface.h
myPluginLoader.h

-pluginA/interfaceA.h
-pluginA/implemA.h

-pluginB/interfaceB.h
-pluginB/implemB.h

etc.

How do I get my pluginB to use classes from pluginA? I have no problem loading the plugins and calling their interface functions from myPluginLoader.h

In implemB.h, I have included ../pluginA/implemA.h and tried to initialize the implemA class, but I get "symbol lookup error" and "undefined symbol: _ZN6implemAC1ERKd"

I figure this is probably because I am linking pluginA to the base (myInterface/myPluginLoader etc.) but not linking pluginA to pluginB (and thus getting name mangling). I tried to export implemA using Q_DECL_EXPORT as:

class Q_DECL_EXPORT implemA
{ ... }

and

class Q_DECL_IMPORT implemB
{ ... }

as described here: QT Doc Creating Shared Libraries
but that gave me the same problem. Any idea how to resolve this?

Thank you!

SGaist

Hi and welome to devnet,

If you have several plugins using shared code then the most simple thing to do is move all the common code in a shared lib that you will link to all the plugins using them.

Joshua195

@SGaist Thanks for the response!

I assume the plugins would link to the shared code in the usual way (-Lshared/path -lsharedlib)?

Is having plugins with dependencies on one another generally considered bad practice?

SGaist

That assumption is corrected.

AFAIK, having linking dependencies between two plugins is not a clean design.