include-what-you-use 可以很方便的检测未使用的头文件，使用的时候绕了点路，google后解决，记录一下。
###1、安装clang ubuntu下直接apt-get 安装就行了。需要注意的是，我的机器上安装clang3.8 后有问题，装了clang3.4后一切正常。暂不研究原因了，先用起来再说。
###2、切换编译器到clang
sudo update-alternatives --config cc sudo update-alternatives --config c++###3、编译 include-what-you-use 参考官方文档就行，没有任何错误。
###4、可以开始玩了 (参考的贴子)
写个CMakeLists.txt cmake_minimum_required(VERSION 3.3 FATAL_ERROR) add_executable(hello main.cc) find_program(iwyu_path NAMES include-what-you-use iwyu) if(NOT iwyu_path) message(FATAL_ERROR "Could not find the program include-what-you-use") else() set_property(TARGET hello PROPERTY CXX_INCLUDE_WHAT_YOU_USE ${iwyu_path}) endif() 写个源码main.cc #include <iostream> #include <vector> int main() { std::cout << "Hello World!" << std::endl; return 0; } 跑跑试试 user@ubuntu:/tmp$ ls ~/hello CMakeLists.txt main.cc user@ubuntu:/tmp$ mkdir /tmp/build user@ubuntu:/tmp$ cd /tmp/build user@ubuntu:/tmp/build$ ~/cmake-3.3.0-rc2-Linux-x86_64/bin/cmake ~/hello -- The C compiler identification is GNU 4.9.2 -- The CXX compiler identification is GNU 4.9.2 -- Check for working C compiler: /usr/bin/cc -- Check for working C compiler: /usr/bin/cc -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Detecting C compile features -- Detecting C compile features - done -- Check for working CXX compiler: /usr/bin/c++ -- Check for working CXX compiler: /usr/bin/c++ -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Detecting CXX compile features -- Detecting CXX compile features - done -- Configuring done -- Generating done -- Build files have been written to: /tmp/build user@ubuntu:/tmp/build$ make Scanning dependencies of target hello [ 50%] Building CXX object CMakeFiles/hello.dir/main.cc.o Warning: include-what-you-use reported diagnostics: /home/user/hello/main.cc should add these lines: /home/user/hello/main.cc should remove these lines: - #include <vector> // lines 2-2 The full include-list for /home/user/hello/main.cc: #include <iostream> // for operator<<, basic_ostream, cout, endl, ostream --- [100%] Linking CXX executable hello [100%] Built target hello user@ubuntu:/tmp/build$ ./hello Hello World! user@ubuntu:/tmp/build$###5、改进一下CMakeLists 上面的CMakeLists不太适合产品使用，因为打印太多了，可以在需要的时候再打开include-what-you-use。
cmake_minimum_required(VERSION 3.3 FATAL_ERROR) add_executable(hello main.cc) if (ENABLE_IWYU) find_program(iwyu_path NAMES include-what-you-use iwyu) if(NOT iwyu_path) message(FATAL_ERROR "Could not find the program include-what-you-use") else() set_property(TARGET hello PROPERTY CXX_INCLUDE_WHAT_YOU_USE ${iwyu_path}) endif() endif()用法：
cmake . -DENABLE_IWYU=ON