What went wrong:
Execution failed for task ':app:externalNativeBuildRelease'.
Build command failed.
Error while executing process D:\androidsdk_cannary\Sdk\cmake\3.6.4111459\bin\cmake.exe with arguments {--build D:\androidprojects\SimpleNativeLibrary\app.externalNativeBuild\cmake\release\x86_64 --target opencv2unity}
[1/2] Building CXX object ../../../cxx/release/x86_64/CMakeFiles/opencv2unity.dir/src/main/cpp/opencv2unity.cpp.o
In file included from D:\androidprojects\SimpleNativeLibrary\app\src\main\cpp\opencv2unity.cpp:39:
D:\androidprojects\SimpleNativeLibrary\app\src\main\cpp/common.h:76:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
1 warning generated.
[2/2] Linking CXX shared library D:\androidprojects\SimpleNativeLibrary\app\build\intermediates\cmake\release\obj\x86_64\libopencv2unity.so
FAILED: cmd.exe /C "cd . && D:\androidsdk_cannary\Sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe --target=x86_64-none-linux-android21 --gcc-toolchain=D:/androidsdk_cannary/Sdk/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64 -fPIC --sysroot D:/androidsdk_cannary/Sdk/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64/sysroot -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -Wa,--noexecstack -Wformat -Werror=format-security -stdlib=libc++ -O2 -DNDEBUG -Wl,--exclude-libs,libgcc.a -Wl,--exclude-libs,libatomic.a -static-libstdc++ -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--no-undefined -Qunused-arguments -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -shared -Wl,-soname,libopencv2unity.so -o D:\androidprojects\SimpleNativeLibrary\app\build\intermediates\cmake\release\obj\x86_64\libopencv2unity.so ../../../cxx/release/x86_64/CMakeFiles/opencv2unity.dir/src/main/cpp/opencv2unity.cpp.o D:/androidprojects/SimpleNativeLibrary/app/src/main/jniLibs/x86_64/libopencv_java4.so -llog -latomic -lm && cd ."
D:\androidprojects\SimpleNativeLibrary\app\src\main\cpp/opencv2unity.cpp:169: error: undefined reference to 'cv::dnn::dnn4_v20181205::NMSBoxes(std::__ndk1::vector<cv::rect_<int>, std::__ndk1::allocator<cv::rect_<int> > > const&, std::__ndk1::vector<float, std::__ndk1::allocator<float=""> > const&, float, float, std::__ndk1::vector<int, std::__ndk1::allocator<int=""> >&, float, int)'
D:\androidprojects\SimpleNativeLibrary\app\src\main\cpp/opencv2unity.cpp:265: error: undefined reference to 'cv::CommandLineParser::CommandLineParser(int, char const* const*, std::__ndk1::basic_string<char, std::__ndk1::char_traits<char="">, std::__ndk1::allocator<char> > const&)'
../../../../src/main/cpp/include\opencv2/core/utility.hpp:897: error: undefined reference to 'cv::CommandLineParser::getByName(std::__ndk1::basic_string<char, std::__ndk1::char_traits<char="">, std::__ndk1::allocator<char> > const&, bool, cv::Param, void*) const'
../../../../src/main/cpp/include\opencv2/core/utility.hpp:897: error: undefined reference to 'cv::CommandLineParser::getByName(std::__ndk1::basic_string<char, std::__ndk1::char_traits<char="">, std::__ndk1::allocator<char> > const&, bool, cv::Param, void*) const'
D:\androidprojects\SimpleNativeLibrary\app\src\main\cpp/opencv2unity.cpp:272: error: undefined reference to 'cv::CommandLineParser::CommandLineParser(int, char const* const*, std::__ndk1::basic_string<char, std::__ndk1::char_traits<char="">, std::__ndk1::allocator<char> > const&)'
D:\androidprojects\SimpleNativeLibrary\app\src\main\cpp/opencv2unity.cpp:273: error: undefined reference to 'cv::CommandLineParser::about(std::__ndk1::basic_string<char, std::__ndk1::char_traits<char="">, std::__ndk1::allocator<char> > const&)'
D:\androidprojects\SimpleNativeLibrary\app\src\main\cpp/opencv2unity.cpp:274: error: undefined reference to 'cv::CommandLineParser::has(std::__ndk1::basic_string<char, std::__ndk1::char_traits<char="">, std::__ndk1::allocator<char> > const&) const'
../../../../src/main/cpp/include\opencv2/core/utility.hpp:897: error: undefined reference to 'cv::CommandLineParser::getByName(std::__ndk1::basic_string<char, std::__ndk1::char_traits<char="">, std::__ndk1::allocator<char> > const&, bool, cv::Param, void*) const'
../../../../src/main/cpp/include\opencv2/core/utility.hpp:897: error: undefined reference to 'cv::CommandLineParser::getByName(std::__ndk1::basic_string<char, std::__ndk1::char_traits<char="">, std::__ndk1::allocator<char> > const&, bool, cv::Param, void*) const'
clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.