[Interest] When does Qt load its plugins?
elvstone at gmail.com
Wed Jul 13 14:14:34 CEST 2016
2016-07-13 14:06 GMT+02:00 Elvis Stansvik <elvstone at gmail.com>:
> 2016-07-13 14:00 GMT+02:00 alexander golks <alex at golks.de>:
>> Am Wed, 13 Jul 2016 12:37:22 +0200
>> schrieb Elvis Stansvik <elvstone at gmail.com>:
>>> 2016-07-13 12:34 GMT+02:00 Elvis Stansvik <elvstone at gmail.com>:
>>> > I'm working on packaging an application using QtWidgets as an AppImage
>>> > and I'm looking at which of the Qt plugins I must bundle.
>>> > I'll run an strace while using the application, but I thought I'd also
>>> > ask here: When in general does Qt load its plugins? For some plugins
>>> > (such as the platform plugin), I expect it to be quite early. But what
>>> > about imageformat plugins, is there a policy that they be loaded as
>>> > late as possible?
>>> To clarify, I wasn't only talking about imageformat plugins, but
>>> plugins in general. The imageformat plugins was just an example where
>>> I suspect they may be loaded as late as possible?
>>> > In short I'm wondering if I must use every nook and cranny of the
>>> > application during my strace run, to catch all plugins, or if it's
>>> > enough to say wait until the QApplication and QMainWindow is up.
>>> > Thanks in advance,
>>> > Elvis
>> i would not use strace to get a packaging list for the plugins to deploy.
>> simply use the plugins you want/need.
>> plugins are loaded when requested first time. so its not safe to wait
>> until QApplication and QMainWindow are up.
> Alright, yes I realized this after I sent my first mail (see my other
> mail just now).
> It's easy to know that if I say want to load JPEGs, I need the
> imageformats/libqjpeg.so plugin. But there are so many plugins in a Qt
> installation it's hard as an application developer to know for sure
> which you need.
> In the Qt I'm using to build this AppImage, there's currently:
If I'm going to guess a little:
I don't think I need these, since I'm not doing anything with a GPS?
These I think are only required by Qt Designer?
These ones I'm unsure about, they sound quite important?
If I want to use SVG icons I'll include this one?
These I'll include according to my requirements, that's easy.
These ones's I'm unsure about. They could be important.. or are they
just for specialized input methods?
Out of these I think I'll only need the XCB plugin, since my app is
exclusively for X11.
This one I don't need, unless I want my application to integrate
better in a Gtk-based desktop environment..? (guessing here)
I'll include this if I want CUPS printing support (I think I do).
I'm not using QML, so I won't need these?
And not SQLite, so no need for this.
This one I think is important, but could someone confirm?
So the ones I'm most unsure about are:
But I'd really appreciate clarifications on the other ones as well.
> For some of these it's obvious from their name what they're for, but
> others I have no idea. And I also don't know if they're integral to
> the working of Qt, or if they're expendable (for example the generic/*
> plugins) :/
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