【发布时间】：2018-12-21 12:31:40
【问题描述】：
我正在尝试使用 Qt 和 OpenCV 为 arm64-v8a 编译程序 我创建了一个工具包来使用 Qt 的 arm64-v8a 版本，但我得到了大量未定义的引用错误
我使用以下参数编译了 Qt：
./configure -xplatform android-clang \
--disable-rpath -nomake tests -nomake examples \
-android-ndk <ndk-r16b-root> -android-sdk <sdk-root> -android-ndk-host linux-x86_64 \
-android-toolchain-version 4.9 -android-ndk-platform android-21 -android-arch arm64-v8a \
-skip qttranslations -skip qtserialport -skip qtwebengine -no-warnings-are-errors \
-prefix <install-dir> -opensource -confirm-license
然后我添加了 2 个编译器，第一个用于 C，第二个用于 C++：
<ndk-r16b-root>/toolchains/llvm/prebuilt/linux-x86_64/bin/clang
使用 ABI：
<ndk-r16b-root>/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++
使用 ABI：
我为此版本的 Qt 克隆了自动检测工具包并使用了以下设置：
Device type : Android Device
Device : Run on Android (default for Android)
Sysroot : <ndk-r16b-root>/platforms/android-21/arch-arm64
Compilers : the 2 above
Android GDB server : <ndk-r16b-root>/prebuilt/android-arm64/gdbserver/gdbserver
Qt version : the one I just compiled
Qt mkspec : android-clang
其他字段默认为空
我的 .pro 文件如下所示：
QT += quick multimedia multimediawidgets
CONFIG += c++11
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
HEADERS += <my-headers>
SOURCES += <my-sources>
RESOURCES += qml/qml.qrc
INCLUDEPATH += OpenCV-android-sdk/sdk/native/jni/include
LIBS += -L"OpenCV-android-sdk/sdk/native/3rdparty/libs/arm64-v8a"\
-L"OpenCV-android-sdk/sdk/native/libs/arm64-v8a"\
-llibtiff\
-llibjpeg\
-llibjasper\
-llibpng\
-lIlmImf\
-llibwebp\
-lopencv_core\
-ltbb\
-lopencv_flann\
-lopencv_imgproc\
-lopencv_highgui\
-lopencv_features2d\
-lopencv_calib3d\
-lopencv_ml\
-lopencv_objdetect\
-lopencv_video\
-lopencv_photo\
-lopencv_videostab\
-ltegra_hal\
-lopencv_imgcodecs\
-lopencv_shape\
-lopencv_stitching\
-lopencv_superres\
-lopencv_videoio
# Additional import path used to resolve QML modules in Qt Creator's code model
QML_IMPORT_PATH =
# Additional import path used to resolve QML modules just for Qt Quick Designer
QML_DESIGNER_IMPORT_PATH =
# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target
DISTFILES += \
android/AndroidManifest.xml \
android/gradle/wrapper/gradle-wrapper.jar \
android/gradlew \
android/res/values/libs.xml \
android/build.gradle \
android/gradle/wrapper/gradle-wrapper.properties \
android/gradlew.bat
ANDROID_PACKAGE_SOURCE_DIR = $$PWD/android
OpenCV-android-sdk 文件夹来自 here 使用 3.2.0 Android 包。
当我尝试编译时，我得到大量未定义的引用，如下所示：
OpenCV-android-sdk/sdk/native/libs/arm64-v8a/libopencv_core.a(matrix.cpp.o): In function `cv::SparseMat::newNode(int const*, unsigned long)':
matrix.cpp:(.text._ZN2cv9SparseMat7newNodeEPKim+0x4b8): undefined reference to `std::__throw_length_error(char const*)'
OpenCV-android-sdk/sdk/native/libs/arm64-v8a/libopencv_core.a(matrix.cpp.o): In function `std::vector<cv::Mat, std::allocator<cv::Mat> >::_M_fill_insert(__gnu_cxx::__normal_iterator<cv::Mat*, std::vector<cv::Mat, std::allocator<cv::Mat> > >, unsigned long, cv::Mat const&)':
matrix.cpp:(.text._ZNSt6vectorIN2cv3MatESaIS1_EE14_M_fill_insertEN9__gnu_cxx17__normal_iteratorIPS1_S3_EEmRKS1_[_ZNSt6vectorIN2cv3MatESaIS1_EE14_M_fill_insertEN9__gnu_cxx17__normal_iteratorIPS1_S3_EEmRKS1_]+0xcd4): undefined reference to `std::__throw_length_error(char const*)'
OpenCV-android-sdk/sdk/native/libs/arm64-v8a/libopencv_core.a(matrix.cpp.o): In function `std::vector<cv::UMat, std::allocator<cv::UMat> >::_M_fill_insert(__gnu_cxx::__normal_iterator<cv::UMat*, std::vector<cv::UMat, std::allocator<cv::UMat> > >, unsigned long, cv::UMat const&)':
matrix.cpp:(.text._ZNSt6vectorIN2cv4UMatESaIS1_EE14_M_fill_insertEN9__gnu_cxx17__normal_iteratorIPS1_S3_EEmRKS1_[_ZNSt6vectorIN2cv4UMatESaIS1_EE14_M_fill_insertEN9__gnu_cxx17__normal_iteratorIPS1_S3_EEmRKS1_]+0xbb0): undefined reference to `std::__throw_length_error(char const*)'
实际使用的链接器命令（发生错误的地方）是：
<ndk-r16b-root>/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++ -D__ANDROID_API__=26 -target aarch64-none-linux-android -gcc-toolchain <ndk-r16b-root>/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64 -Wl,--exclude-libs,libgcc.a --sysroot=<ndk-r16b-root>/platforms/android-26/arch-arm64/ -Wl,-soname,libTest.so -Wl,-rpath-link=<newly-compiled-Qt-root>/lib -Wl,--no-undefined -Wl,-z,noexecstack -shared -o libTest.so myfilter.o qml_main_qml.o qmlcache_loader.o -L<ndk-r16b-root>/sources/cxx-stl/llvm-libc++/libs/arm64-v8a -LOpenCV-android-sdk/sdk/native/3rdparty/libs/arm64-v8a -LOpenCV-android-sdk/sdk/native/libs/arm64-v8a -llibtiff -llibjpeg -llibjasper -llibpng -lIlmImf -llibwebp -lopencv_core -ltbb -lopencv_flann -lopencv_imgproc -lopencv_highgui -lopencv_features2d -lopencv_calib3d -lopencv_ml -lopencv_objdetect -lopencv_video -lopencv_photo -lopencv_videostab -ltegra_hal -lopencv_imgcodecs -lopencv_shape -lopencv_stitching -lopencv_superres -lopencv_videoio -L<newly-compiled-Qt-root>/lib -lQt5Quick -lQt5MultimediaWidgets -lQt5Multimedia -lQt5Widgets -lQt5Gui -lQt5Qml -lQt5Network -lQt5Core -lGLESv2 -lc++ -llog -lz -lm -ldl -lc
编辑：尝试自己编译 OpenCV，效果不佳。
Edit2：我刚刚看到Petesh 那里的答案：https://stackoverflow.com/a/12920944/9987834
这可能是因为我的 Qt 和 OpenCV 版本是使用不同的标准库编译的吗？
Edit3：无法正确编译 OpenCV，我收到类似这样的错误：
skipping incompatible /usr/local/lib/libopencv_core.a when searching for -lopencv_core
Edit4：出于某种原因，OpenCV 完全停止编译，给我这样的错误：
In file included from /path/to/opencv-3.2.0/modules/core/src/algorithm.cpp:43:
In file included from /path/to/opencv-3.2.0/modules/core/src/precomp.hpp:84:
In file included from /path/to/opencv-3.2.0/modules/core/include/opencv2/core/hal/intrin.hpp:297:
/path/to/opencv-3.2.0/modules/core/include/opencv2/core/hal/intrin_neon.hpp:285:49: error: expected
unqualified-id
template <typename T> static inline float16x4_t vld1_f16(const T* ptr)
^
<ndk-r16b-root>/toolchains/llvm/prebuilt/linux-x86_64/lib64/clang/5.0.300080/include/arm_neon.h:7745:24: note:
expanded from macro 'vld1_f16'
#define vld1_f16(__p0) __extension__ ({ \
^
[ 31%] Built target libwebp
[ 31%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/command_line_parser.cpp.o
In file included from /path/to/opencv-3.2.0/modules/core/src/algorithm.cpp:43:
In file included from /path/to/opencv-3.2.0/modules/core/src/precomp.hpp:84:
In file included from /path/to/opencv-3.2.0/modules/core/include/opencv2/core/hal/intrin.hpp:297:
/path/to/opencv-3.2.0/modules/core/include/opencv2/core/hal/intrin_neon.hpp:778:8: error: unknown type
name 'v_float16x4'; did you mean 'v_float32x4'?
inline v_float16x4 v_load_f16(const short* ptr)
^~~~~~~~~~~
v_float32x4
我的蛋糕（gui）输出在这里：https://pastebin.com/ZBrtizUi
有人知道为什么吗？
【问题讨论】：
标签： android c++ qt opencv arm64