complling errors on ubuntu 20.04

[zengletian1491]

My computer configurations are:
gcc (Ubuntu 7.5.0-6ubuntu2) 7.5.0
cuda 11.3
cudnn 8.2.1
numpy 1.24.3
pandas 2.0.2
matplotlib 3.7.1
scipy 1.10.1
scikit-mage 0.21.0
scikit-learn 1.2.2
lapack 3.11.0

I installed all the needed dependencies ,but when I typed in:

cmake -D CMAKE_BUILD_TYPE=Release
-D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib-4.7.0/modules
-D OPENCV_ENABLE_NONFREE=ON
-D WITH_OPENMP=ON
-D WITH_TBB=ON
-D WITH_QT=ON
-D CUDA_NVCC_FLAGS="--Wno-deprecated-gpu-targets"
-D OPENCV_EXTRA_EXE_LINKER_FLAGS=-latomic
-D ENABLE_PRECOMPILED_HEADERS=OFF
-D WITH_CUDA=ON
-D WITH_CUDNN=ON
-D ENABLE_FAST_MATH=ON
-D CUDA_FAST_MATH=ON
-D WITH_CUBLAS=ON
-D PYTHON3_EXECUTABLE=/usr/bin/python3
-D PYTHON3_INCLUDE_DIR=/usr/include/python3.8
-D PYTHON3_LIBRARY=/usr/lib/python3.8/config-3.8-x86_64-linux-gnu/libpython3.8.so
-D PYTHON3_PACKAGES_PATH=$(/usr/bin/python3 -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())")
-D PYTHON3_NUMPY_INCLUDE_DIRS=$(/usr/bin/python3 -c "import numpy as np;import os; print(os.path.dirname(np.file)+'/core/include')")
-D OPENCV_GENERATE_PKGCONFIG=ON
-D CMAKE_INSTALL_PREFIX=/usr/local/opencv4
..
sudo make

Errors occurred as follows:

[ 57%] Automatic MOC for target opencv_cvv
[ 57%] Built target opencv_cvv_autogen
[ 57%] Building CXX object modules/cvv/CMakeFiles/opencv_cvv.dir/opencv_cvv_autogen/mocs_compilation.cpp.o
In file included from /home/Software/opencv4/opencv_contrib-4.7.0/modules/cvv/src/gui/overview_panel.hpp:12:0,
from /home/Software/opencv4/opencv_contrib-4.7.0/modules/cvv/src/gui/main_call_window.hpp:9,
from /home/Software/opencv4/opencv-4.7.0/build/modules/cvv/opencv_cvv_autogen/MXUWEOXILK/moc_main_call_window.cpp:10,
from /home/Software/opencv4/opencv-4.7.0/build/modules/cvv/opencv_cvv_autogen/mocs_compilation.cpp:6:
/home/Software/opencv4/opencv_contrib-4.7.0/modules/cvv/src/gui/../stfl/stfl_engine.hpp:31:42: error: ‘constexpr const QString::SplitBehavior Qt::SkipEmptyParts’ redeclared as different kind of symbol
static constexpr QString::SplitBehavior SkipEmptyParts = QString::SkipEmptyParts;
^~~~~~~~~~~~~~
In file included from /opt/Qt5.14.2/5.14.2/gcc_64/include/QtCore/qbytearray.h:45:0,
from /opt/Qt5.14.2/5.14.2/gcc_64/include/QtCore/qstring.h:50,
from /opt/Qt5.14.2/5.14.2/gcc_64/include/QtCore/QString:1,
from /home/Software/opencv4/opencv_contrib-4.7.0/modules/cvv/src/gui/call_tab.hpp:4,
from /home/Software/opencv4/opencv-4.7.0/build/modules/cvv/opencv_cvv_autogen/MXUWEOXILK/moc_call_tab.cpp:10,
from /home/Software/opencv4/opencv-4.7.0/build/modules/cvv/opencv_cvv_autogen/mocs_compilation.cpp:2:
/opt/Qt5.14.2/5.14.2/gcc_64/include/QtCore/qnamespace.h:199:9: note: previous declaration ‘Qt::SplitBehaviorFlags SkipEmptyParts’
SkipEmptyParts = 0x1,
^~~~~~~~~~~~~~
make[2]: *** [modules/cvv/CMakeFiles/opencv_cvv.dir/build.make:63：modules/cvv/CMakeFiles/opencv_cvv.dir/opencv_cvv_autogen/mocs_compilation.cpp.o] 错误 1
make[1]: *** [CMakeFiles/Makefile2:7805：modules/cvv/CMakeFiles/opencv_cvv.dir/all] 错误 2
make: *** [Makefile:163：all] 错误 2
zengletian@zengletian-ThinkStation-P520c:/home/Software/opencv4/opencv-4.7.0/build$

Could you give me some suggestions?Thanks very much!

[Kumataro]

Hello, I think this problem is related with #3285 .

I tried Ubuntu 20.04LTS with official Qt 5.12.8 apt packages, but there are no problem.

cvv module has workaroud to change from QString::SplitBehavior to Qt::SplitBehavior .

opencv_contrib/modules/cvv/src/stfl/stfl_engine.hpp

Lines 26 to 33 in 353e37e

	// WORKAROUND:
	// - Qt::SplitBehavior introduced in 5.14, QString::SplitBehavior was removed in Qt6
	// - Support required part of Qt::SplitBehavior from 5.15 for older Qt versions
	#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)
	namespace Qt {
	static constexpr QString::SplitBehavior SkipEmptyParts = QString::SkipEmptyParts;
	}
	#endif

QT_VERSION	Qt::SplitBehavior	QString::SplitBehaviour	CVV Workaround
5.12.x	N/S	Supported	Enable
5.13.x	N/S	Suppotted	Enable
5.14.x	Supported	Supported	Enable
5.15.x	Supported	Supported(Deprecated)	Disable
6.0.x	Supported	N/S	Disable

• 5.12,x : CVV module defines Qt::SkipEmptyParts in stfl_engine.hpp.
• 5.15,x : QtCore defines Qt::SkipEmptyParts in qnamespace.h .
• 6.0.x : QtCore defines Qt::SkipEmptyParts in qnamespace.h .

But it seems that this workaround is not good for Qt 5.14.

• 5.14,x : CVV module defines Qt::SkipEmptyParts in stfl_engine.hpp and QtCore defines Qt::SkipEmptyParts in qnamespace.h .

Sorry, ubuntu doesn't support Qt 5.14. So testing is hard for me ( it needs to compile from source code). 20.04LTS supports 5.12.8, 22.04LTS/22.10/... support 5.15 series.

Could you try to it ?

- #if QT_VERSION < QT_VERSION_CHECK(5, 15, 0) 
+ #if QT_VERSION < QT_VERSION_CHECK(5, 14, 0) 

[zengletian1491]

When I change “ if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)” to “ if QT_VERSION < QT_VERSION_CHECK(5, 14, 0) ”， the compiling process works well ! Thanks very much!