Details
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Bug
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Resolution: Duplicate
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P2: Important
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None
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6.2.7, 6.4.2, 6.5.0 Beta1
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Linux/X11,
Windows
Description
Attached are 2 projects which consist of a simple static QML plugin and a simple application that uses that plugin:
└── MyModule
├── CMakeLists.txt
├── MyItem.qml
└── MyApp
├── CMakeLists.txt
├── main.cpp
├── main.qml
Relevant parts of <ROOT>/MyModule/CMakeLists.txt:
project(MyModule)
if (NOT DEFINED MY_QML_DIR)
set(MY_QML_DIR ${CMAKE_SOURCE_DIR}/../qml)
endif()
set(QT_QML_OUTPUT_DIRECTORY ${MY_QML_DIR})
qt_add_qml_module(MyModule
URI MyModule
VERSION 1.0
STATIC
QML_FILES MyItem.qml
)
Relevant parts of <ROOT>/MyApp/CMakeLists.txt:
project(MyApp)
if (NOT DEFINED MY_QML_DIR)
set(MY_QML_DIR ${CMAKE_SOURCE_DIR}/../qml)
endif()
qt_add_executable(appMyApp
main.cpp
)
qt_add_qml_module(appMyApp
URI MyApp
VERSION 1.0
IMPORTS MyModule
IMPORT_PATH ${MY_QML_DIR}
QML_FILES main.qml
)
target_link_directories(appMyApp PRIVATE ${MY_QML_DIR}/MyModule)
target_link_libraries(appMyApp
PRIVATE Qt6::Quick MyModuleplugin)
Relevant parts of <ROOT>/MyApp/main.cpp:
int main(int argc, char *argv[]) { Q_IMPORT_QML_PLUGIN(MyModulePlugin); // ... }
Steps to reproduce
- Build <ROOT>/MyModule/CMakeLists.txt as a standalone project
- Build <ROOT>/MyApp/CMakeLists.txt as a standalone project (using the same Kit as above)
Outcome
Step #1 builds fine, but Step #2 fails:
/usr/bin/ld: <ROOT>/qml/MyModule/libMyModuleplugin.a(MyModuleplugin_MyModulePlugin.cpp.o): in function `qt_plugin_instance_MyModulePlugin()':
MyModuleplugin_MyModulePlugin.cpp:(.text+0xc2): undefined reference to `qml_register_types_MyModule()'
/usr/bin/ld: <ROOT>/qml/MyModule/libMyModuleplugin.a(MyModuleplugin_MyModulePlugin.cpp.o): in function `QtPrivate::QMetaTypeForType<MyModulePlugin>::getDefaultCtr()::{lambda(QtPrivate::QMetaTypeInterface const*, void*)#1}::_FUN(QtPrivate::QMetaTypeInterface const*, void*)':
MyModuleplugin_MyModulePlugin.cpp:(.text._ZZN9QtPrivate16QMetaTypeForTypeI14MyModulePluginE13getDefaultCtrEvENUlPKNS_18QMetaTypeInterfaceEPvE_4_FUNES5_S6_[_ZZN9QtPrivate16QMetaTypeForTypeI14MyModulePluginE13getDefaultCtrEvENUlPKNS_18QMetaTypeInterfaceEPvE_4_FUNES5_S6_]+0x2e): undefined reference to `qml_register_types_MyModule()'
...even though nm -C libMyModuleplugin.a shows that qml_register_types_MyModule() exists.
Workaround
Merge both projects into a single CMake tree by adding <ROOT>/CMakeLists.txt (which is already provided in the attachment):
cmake_minimum_required(VERSION 3.16)
project(MyMergedProject)
set(MY_QML_DIR ${CMAKE_SOURCE_DIR}/qml)
add_subdirectory(MyModule)
add_subdirectory(MyApp)
This lets us successfully build and run the application.
Notes
- When merging into a single project tree, _Q_IMPORT_QML_PLUGIN()_ is not necessary
- When building MyApp as standalone project, building/linking completes without errors if _Q_IMPORT_QML_PLUGIN()_ is removed. However, this means the QML resources become unavailable at runtime.
Attachments
Issue Links
- duplicates
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- Reported
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- relates to
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- Reported
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- Open
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