CMake调用两个NDK编译Ceres库失败，求原因及解决办法

我正尝试按照官方文档在Android平台构建Ceres库，但遇到编译错误无法推进。我并非构建工具专家，若问题较为基础还请见谅。目前核心问题是：CMake同时使用了我通过Android Studio安装的NDK，以及Visual Studio开启安卓开发功能后自带的NDK，导致编译测试程序失败。

执行的CMake命令 #

cmake -DCMAKE_TOOLCHAIN_FILE="C:\Users\l.gagliano\AppData\Local\Android\Sdk\ndk\16.1.4479499\build\cmake\android.toolchain.cmake" -DEigen3_DIR=D:\DEV\ceres\eigen\build -DANDROID_ABI=arm64-v8a -DANDROID_STL=c++_shared -DANDROID_NATIVE_API_LEVEL=android-21 -DBUILD_SHARED_LIBS=ON -DMINILOG=ON D:\DEV\ceres\ceres-solver-2.1.0

编译错误输出 #

-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - failed
-- Check for working C compiler: C:/Users/l.gagliano/AppData/Local/Android/Sdk/ndk/16.1.4479499/toolchains/llvm/prebuilt/windows-x86_64/bin/clang.exe
-- Check for working C compiler: C:/Users/l.gagliano/AppData/Local/Android/Sdk/ndk/16.1.4479499/toolchains/llvm/prebuilt/windows-x86_64/bin/clang.exe - broken
CMake Error at C:/Program Files/CMake/share/cmake-3.25/Modules/CMakeTestCCompiler.cmake:70 (message):
  The C compiler

    "C:/Users/l.gagliano/AppData/Local/Android/Sdk/ndk/16.1.4479499/toolchains/llvm/prebuilt/windows-x86_64/bin/clang.exe"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: D:/DEV/ceres/ceres-android/CMakeFiles/CMakeScratch/TryCompile-lab0em

    Run Build Command(s):C:/Program Files (x86)/Microsoft Visual Studio/2019/Professional/MSBuild/Current/Bin/MSBuild.exe cmTC_366ff.vcxproj /p:Configuration=Debug /p:Platform=x64 /p:VisualStudioVersion=16.0 /v:m && Microsoft (R) Build Engine version 16.11.2+f32259642 for .NET Framework
    Copyright (C) Microsoft Corporation. All rights reserved.

      ANDROID_HOME=C:\\Microsoft\AndroidSDK\25
      ANT_HOME=C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\Apps\apache-ant-1.9.3
      JAVA_HOME=C:\Program Files\Eclipse Foundation\jdk-8.0.302.8-hotspot
      NDK_ROOT=C:\\Microsoft\AndroidNDK64\android-ndk-r16b
      testCCompiler.c
      In file included from <built-in>:327:
    <command line>(3,9): warning : '__ANDROID_API__' macro redefined [-Wmacro-redefined] [D:\DEV\ceres\ceres-android\CMakeFiles\CMakeScratch\TryCompile-lab0em\cmTC_366ff.vcxproj]
      #define __ANDROID_API__ 21
              ^
      <command line>(1,9):  note: previous definition is here
      #define __ANDROID_API__ 19
              ^
      1 warning generated.
      C:\\Microsoft\AndroidNDK64\android-ndk-r16b\toolchains\x86_64-4.9\prebuilt\windows-x86_64/lib/gcc/x86_64-linux-android/4.9.x/../../../../x86_64-linux-android/bin\ld: error: cmTC_366ff.dir\Debug\testCCompiler.o: incompatible target
      clang.exe: error: linker command failed with exit code 1 (use -v to see invocation)
    C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Microsoft\VC\v160\Application Type\Android\3.0\Android.Common.targets(119,5): error MSB6006: "clang.exe" exited with code 1. [D:\DEV\ceres\ceres-android\CMakeFiles\CMakeScratch\TryCompile-lab0em\cmTC_366ff.vcxproj]




  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:60 (project)


-- Configuring incomplete, errors occurred!
See also "D:/DEV/ceres/ceres-android/CMakeFiles/CMakeOutput.log".
See also "D:/DEV/ceres/ceres-android/CMakeFiles/CMakeError.log".

问题原因 #

1. 环境变量冲突：系统环境变量中的NDK_ROOT指向Visual Studio自带的NDK，但你指定的CMAKE_TOOLCHAIN_FILE是Android Studio安装的NDK路径，导致两个NDK混合调用。
2. 架构不匹配：你指定了ANDROID_ABI=arm64-v8a，但链接器使用的是Visual Studio NDK的x86_64工具链，生成的目标文件架构不兼容，引发链接错误。
3. API级别重定义：Visual Studio的NDK默认设置__ANDROID_API__=19，与你指定的android-21冲突，导致宏重定义警告，进而触发后续编译失败。

解决办法 #

• 清理冲突环境变量：
  打开系统环境变量设置，暂时清空或删除NDK_ROOT、ANDROID_HOME变量，打开新的命令提示符（确保环境变量生效）后重新执行CMake命令。
• 明确指定NDK路径：
  在CMake命令中添加-DANDROID_NDK参数，强制指定Android Studio的NDK路径，覆盖环境变量影响：

  cmake -DCMAKE_TOOLCHAIN_FILE="C:\Users\l.gagliano\AppData\Local\Android\Sdk\ndk\16.1.4479499\build\cmake\android.toolchain.cmake" -DANDROID_NDK="C:\Users\l.gagliano\AppData\Local\Android\Sdk\ndk\16.1.4479499" -DEigen3_DIR=D:\DEV\ceres\eigen\build -DANDROID_ABI=arm64-v8a -DANDROID_STL=c++_shared -DANDROID_NATIVE_API_LEVEL=android-21 -DBUILD_SHARED_LIBS=ON -DMINILOG=ON D:\DEV\ceres\ceres-solver-2.1.0
  

• 切换构建生成器：
  若不需要Visual Studio构建安卓项目，可指定CMake使用Ninja或Makefiles生成器，避免调用MSBuild：

  cmake -G "Ninja" -DCMAKE_TOOLCHAIN_FILE="C:\Users\l.gagliano\AppData\Local\Android\Sdk\ndk\16.1.4479499\build\cmake\android.toolchain.cmake" -DANDROID_NDK="C:\Users\l.gagliano\AppData\Local\Android\Sdk\ndk\16.1.4479499" -DEigen3_DIR=D:\DEV\ceres\eigen\build -DANDROID_ABI=arm64-v8a -DANDROID_STL=c++_shared -DANDROID_NATIVE_API_LEVEL=android-21 -DBUILD_SHARED_LIBS=ON -DMINILOG=ON D:\DEV\ceres\ceres-solver-2.1.0
  

  注意：使用Ninja需提前安装该构建工具。

内容的提问来源于stack exchange，提问作者user8469759