Qt Designer custom widget plugin confusion
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wrote on 24 Jan 2024, 20:10 last edited by Jesse Dosher
I've been creating and using custom widget plugins for Qt Designer (and Designer running in Qt Creator) for many years now, and I've occasionally run into a bit of a struggle doing that. The struggle is happening again, and it's brought up something I'm rather confused by.
It's been stated that the version of Qt used to build a custom widget plugin needs to match the same version Designer (or designer run inside of Creator) was built with. But if that's so, I'm confused about that because I've built the Qwt (Qt Widgets for Technical Applications) library using Qt 6.5.3 and yet those Qwt widgets show up in designer/creator, which reports it was built with Qt 6.6.0. So it appear there is a way to run custom widget plugins built with a different version of Qt. I've looked through the .pro and .pri files in qwt source trying to figure out what the trick is, but to no avail.
My current Qt install used qt-unified-linux-x64-4.6.1-online.
A related confusion is that 'About plugins' doesn't list qwt, but I do see it in the shell when running with QT_DEBUG_PLUGINS=1 I don't, however, see any mention of my plugin (errors or otherwise). My plugin install path is in QT_PLUGIN_PATH, so it's not a path issue.
But the real question is: how does Qwt get around the version issue, and how can a mere mortal, such as I, do the same?
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I've been creating and using custom widget plugins for Qt Designer (and Designer running in Qt Creator) for many years now, and I've occasionally run into a bit of a struggle doing that. The struggle is happening again, and it's brought up something I'm rather confused by.
It's been stated that the version of Qt used to build a custom widget plugin needs to match the same version Designer (or designer run inside of Creator) was built with. But if that's so, I'm confused about that because I've built the Qwt (Qt Widgets for Technical Applications) library using Qt 6.5.3 and yet those Qwt widgets show up in designer/creator, which reports it was built with Qt 6.6.0. So it appear there is a way to run custom widget plugins built with a different version of Qt. I've looked through the .pro and .pri files in qwt source trying to figure out what the trick is, but to no avail.
My current Qt install used qt-unified-linux-x64-4.6.1-online.
A related confusion is that 'About plugins' doesn't list qwt, but I do see it in the shell when running with QT_DEBUG_PLUGINS=1 I don't, however, see any mention of my plugin (errors or otherwise). My plugin install path is in QT_PLUGIN_PATH, so it's not a path issue.
But the real question is: how does Qwt get around the version issue, and how can a mere mortal, such as I, do the same?
A plugin built with an older Qt version than the app wich is using this plugin is fine. It can not be newer for obvious reasons as the plugin might use a new api call.
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