A lot of plugins questions.
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Hello all,
I have some questions to Qt4 masters,
I'm the developer of "GLC_lib":http://www.glc-lib.net and "GLC_Player":http://www.glc-player.net... From now, I need to use more powerful functionality of Qt4.
To do that, I have done some research and I'haven't found clear answer about plugin's related questions :Can I use Plugins in a DLL which depend of this DLL (ia GLC_lib plugins which depends of GLC_lib)
It's possible to catch exceptions in a plugin ?
It's possible to use more than one interface in a plugin implementation ?
It's possible to send signals to a plugin class ?
If yes, where I should declare signals ? (In the interface or in the implementation of the plugin or somewhere else?)
It's possible to receive signals from a plugin class ?
If yes, where I should declare signals ? (In the interface or in the implementation of the plugin or somewhere else?)
It's possible to use a powerful plugin class which use a some QWidget with Signals and Slots ?
And finally, if the answer is yes have you some samples ?
Thanks.
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bq. Can I use Plugins in a DLL which depend of this DLL (ia GLC_lib plugins which depends of GLC_lib)
Yes.
bq. It's possible to catch exceptions in a plugin ?
Yes. To be useful you would have to know the type of exception. When in doubt, you can do catch(...) but that might also catch exceptions that you don't know how to handle.
@try {
myPlugin->doSomething();
} catch(SomeException &ex) {
qWarning("Exception occurred");
}@bq. It's possible to use more than one interface in a plugin implementation ?
Yes.
@class MyPlugin : public Interface1, public Interface2, public QObject
{
Q_OBJECT
Q_INTERFACES(Interface1 Interface2)// The rest of your class implementation};@
bq. It's possible to send signals to a plugin class ?
Yes. You can send signals everywhere. Or better said, you can connect signals and slots to any signal you can access.
bq. If yes, where I should declare signals ? (In the interface or in the implementation of the plugin or somewhere else?)
You declare signals in the class you emit them from.
bq. It's possible to receive signals from a plugin class ?
Yes.
bq. If yes, where I should declare signals ? (In the interface or in the implementation of the plugin or somewhere else?)
Declare them in your plug-in implementation. One of the drawbacks of the plug-in system is that you cannot publicly declare signals and slots without the plug-in being dependent on a dll that implements the QObject part of the interface.
@class MyPlugin : public Interface1, public QObject
{
Q_OBJECT
Q_INTERFACES(Interface1)Q_SIGNALS:
void progressChanged(int);// The rest of your class implementation};@
bq. It's possible to use a powerful plugin class which use a some QWidget with Signals and Slots ?
Yes.