编译报错: undefined reference to `google::FlagRegisterer::FlagRegisterer解决方法

一、问题描述

编译报错

CMakeFiles/run_mapping_offline.dir/run_mapping_offline.cc.o: In function `__static_initialization_and_destruction_0': /home/wong/workspace_demo/packagetest_faster_lio_ws/src/***/***/app/run_mapping_offline.cc:16: undefined reference to `google::FlagRegisterer::FlagRegisterer<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >(char const*, char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*)' /home/wong/workspace_demo/packagetest_faster_lio_ws/src/***/***/app/run_mapping_offline.cc:17: undefined reference to `google::FlagRegisterer::FlagRegisterer<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >(char const*, char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*)'
/home/wong/workspace_demo/***/src/***/***/app/run_mapping_offline.cc:18: undefined reference to `google::FlagRegisterer::FlagRegisterer<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >(char const*, char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*)' /home/wong/workspace_demo/***/src/***/***/app/run_mapping_offline.cc:19: undefined reference to `google::FlagRegisterer::FlagRegisterer<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >(char const*, char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*)' collect2: error: ld returned 1 exit status ***/***/app/CMakeFiles/run_mapping_offline.dir/build.make:678: recipe for target '/home/wong/workspace_demo/***/devel/lib/faster_lio/run_mapping_offline' failed

二、解决方法

自己的解决方法是在 CMakeLists.txt 中添加下列语句：

find_package(gflags REQUIRED)

这个是自己的解决方法，如果不适用屏幕前的朋友，可以参考最后的参考链接。

参考链接

[1] weixin_43767344. undefined reference to ‘google::FlagRegisterer::FlagRegisterer [EB/OL]. https://blog.csdn.net/weixin_43767344/article/details/103799983, 2020-01-02/2022-07-27.