Question

目标：使用带有Conan和OpenCV的交叉编译构建脚本为Android编译外部库。

我今天的环境：

OS： MacOS High Sierra 10.13.6 ;
柯南： 1.7.3 ../Cellar/conan/1.6.1/bin/conan
Python： 2.7.10 /usr/bin/python（也尝试过3个）
GCC / C ++： 8.2.0 /opt/local/bin/gcc-mp-8 || /opt/local/bin/g++-mp-8（由于clang使用c ++而被引用）
Clang / Clang ++： 9.1.0 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin（这不是程序使用的语言）
CMake： 3.12.2 /Applications/CMake.app/Contents/bin/cmake
使用的NDK： 17

问题：Open CV无法编译C ++。主要信息是

-- The CXX compiler identification is Clang 6.0.2
-- The C compiler identification is Clang 6.0.2
-- Check for working CXX compiler: /Users/<user>/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++
-- Check for working CXX compiler: /Users/<user>/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ -- broken
CMake Error at /Applications/CMake.app/Contents/share/cmake-3.12/Modules/CMakeTestCXXCompiler.cmake:45 (message):
The C++ compiler

"/Users/<user>/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++"

is not able to compile a simple test program.

It fails with the following output:

Change Dir: /Users/<user>/.conan/data/OpenCV/3.4.1/ins/stable/build/4492059a128c69658616e0cf3d3f007e2ce6603c/CMakeFiles/CMakeTmp

Run Build Command:"/Users/<user>/Library/Android/sdk/cmake/3.6.4111459/bin/ninja" "cmTC_4338c"
[1/2] Building CXX object CMakeFiles/cmTC_4338c.dir/testCXXCompiler.cxx.o
[2/2] Linking CXX executable cmTC_4338c
FAILED: : && /Users/<user>/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ --sysroot=/Users/<user>/Library/Android/sdk/ndk-bundle/sysroot   -Wl,-search_paths_first -Wl,-headerpad_max_install_names  CMakeFiles/cmTC_4338c.dir/testCXXCompiler.cxx.o  -o cmTC_4338c   && :
ld: library not found for -lc++
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

CMake will not be able to correctly generate this project.

CMakeTmp是一个文件夹，为空。
CMakeError在“ ..fail并显示以下输出”之后显示相同的消息

要求提供 LD库。但是在LLVM文件夹上没有 LLVM-LD ，如果我没记错的话，它在4.0上已被删除。我正在使用10.0。这就是我的文件夹中的内容

肥胖：如您所见，我不知道如何以正确的方式设置旗帜，也不知道这是否会有所改变。

代码：

Buildscript.py

build_dir = "build_Android_Debug"
conan_install_arguments = "-s compiler=clang -s compiler.version=6.0 -s compiler.libcxx=libc++ -s os=Android -s os.api_level=26 -s arch=armv8 -s build_type=Debug"

android_cmake_toolchain_path = current_dir_absolute_path + "/cmake-toolchains/Android.cmake"
conan_install_arguments += " --env CONAN_CMAKE_TOOLCHAIN_FILE=\"%s\"" % android_cmake_toolchain_path

conan_install_arguments += " --env CONAN_CMAKE_FIND_ROOT_PATH=/Users/<user>/Library/Android/sdk/ndk-bundle/sysroot"
conan_install_arguments += " --env PATH=[/Users/<user>/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin]"
conan_install_arguments += " --env AR=llvm-ar"
conan_install_arguments += " --env AS=llvm-as"
conan_install_arguments += " --env CC=clang"
conan_install_arguments += " --env CXX=clang++"

conan_install_command = "cd %s && conan install .. %s" % (build_dir, conan_install_arguments)

os.system(conan_install_command)

Android.cmake

set(CMAKE_MAKE_PROGRAM /Users/vcanato/Library/Android/sdk/cmake/3.6.4111459/bin/ninja)
set(CMAKE_ANDROID_NDK /Users/vcanato/Library/Android/sdk/ndk-bundle/)

我已经尝试过的内容

关于构建脚本

compiler=clang
compiler.version=5.0
compiler.libcxx=libc++
os=Android
os.api_level=21
arch=armv7

Obs：不建议使用Gcc，因此如果没有，则将是一个很好的解决方案，但仍然无法正常工作。

compiler=gcc
compiler.version=4.9
compiler.libcxx=libstdc++
os=Android
os.api_level=21
arch=armv7
build_type=Release

在Android.cmake上：

cmake_minimum_required(VERSION 3.4 FATAL_ERROR)
include_directories("/usr/local/Cellar/gcc/8.2.0/include/c++/8.2.0")
include_directories( "/usr/local/Cellar/gcc/8.2.0/include/c++/8.2.0/x86_64-apple-darwin17.7.0/bits")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -I /usr/local/include/c++/8.2.0/")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -X /usr/include/c++/4.2.1/")
set(CMAKE_CXX_STANDARD 11)
set(CXX_STANDARD_REQUIRED)
set(CMAKE_CXX_COMPILER "/usr/bin/g++")
set(CMAKE_CXX_COMPILER "/Users/vcanato/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++")
set(CMAKE_C_COMPILER "/usr/bin/gcc")
set(ANDROID_ABI arm64-v8a)
set(CMAKE_ANDROID_API android-21)
set(CMAKE_BUILD_TYPE Debug)
set(CMAKE_TOOLCHAIN_FILE /Users/<user>/Library/Android/sdk/ndk-bundle/build/cmake/android.toolchain.cmake)

set(CMAKE_ANDROID_NDK /Users/<user>/Library/Android/sdk/ndk-bundle/ CACHE FILEPATH "")

在CmakeList.txt上

set(CMAKE_CXX_COMPILER "/Users/vcanato/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++")
set(CMAKE_CXX_COMPILER "/usr/bin/g++")

project()之前和之后

工具链：

/Users/vcanato/Library/Android/sdk/ndk-bundle/toolchains/arm-linux-androideabi-4.9
/Users/vcanato/Library/Android/sdk/ndk-bundle/toolchains/x86_64-4.9

我什至尝试构建自己的standalone toolchain并使用Conan cross building guide to Android

关于Stack和GitHub的类似问题：

Answer 1

在工具链中指定CMAKE_MAKE_COMMAND的正确方法是设置 CACHE 变量：

set(CMAKE_MAKE_PROGRAM /Users/vcanato/Library/Android/sdk/cmake/3.6.4111459/bin/ninja
    CACHE FILEPATH "")

这意味着by documentation（如果变量是由生成器设置的，则设置了CACHE版本）和this CMake mailing中的含义。

在OpenCV上。 C ++编译器无法编译简单的测试程序。使用Clang ++

1 个答案:

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