Windows - qt_add_qml_module failed to load the plugin

dheerendra

Hi All

Unable to load the plugin created using qt_add_qml_module
CMake on Windows , Qt 6.6.3, Mingw_64.
Creating the library & adding new qml module using
qt_add_qml_module(..)

This creates the plugin.

However when I import in QML, it is unable to load the plugin.
I tried to load the plugin using QPluginLoader. This also fails.

Same CMake configuration works on Linux without any change.

Anyone facing similar issue ?

dheerendra

Here is the answer - qt_add_qml_module builds plugin & one shared library. Both have to be in path. I tried to add the path using the addLibraryPath. Adding the path using addLibraryPath did not help. Finally I modified the path environment variable. It started working.

May be bug with addLibraryPath. Need to file a bug on this.
add the path of the shared library & plugin to environment variable. It works.

JKSH

@dheerendra Thanks for sharing your solution! There is no bug, however.

qt_add_qml_module() generates 2 library targets by default: One "backing target" like MyModule.dll (which contains your actual QML code) and one "plugin target" like MyModuleplugin.dll (which contains plugin interface)

Your backing target must be put in one of Windows' standard DLL search paths (see https://learn.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-search-order#standard-search-order-for-unpackaged-apps ) -- usually, you would put it next to your *.exe (or you could also put it in one of your PATH folders).
Your plugin target must be put in a "module folder". This "module folder"...
- ...must have the same name as your QML module
- ...must contain your plugin target AND the module definition files (qmldir file + *.qmltypes file)
- ...must be found inside of your QML engine's import paths. See https://doc.qt.io/qt-6/qqmlengine.html#importPathList

dheerendra

@JKSH True. Agree with you. Expectation was that after adding the library path it should work. This is where my confusion.

QtTester

@dheerendra can you show some demo source? I don't konw how to write qml plugin and use the component in app.qml, thank you .