解决undefined reference to symbol ‘pthread_condattr_setclock@@GLIBC_2.3.3‘

解决undefined reference to symbol ‘pthread_condattr_setclock@@GLIBC_2.3.3‘

笔者在ubuntu20 运行DSO时发现遇到如下问题：

[ 87%] Linking CXX executable ../bin/step-59.debug
[ 87%] Linking CXX executable ../bin/step-52.debug
/usr/lib64/gcc/x86_64-suse-linux/7/../../../../x86_64-suse-linux/bin/ld: CMakeFiles/step-59.debug.dir/step-59/step-59.cc.o: undefined reference to symbol ‘pthread_condattr_setclock@@GLIBC_2.3.3‘
/usr/lib64/gcc/x86_64-suse-linux/7/../../../../x86_64-suse-linux/bin/ld: /usr/lib64/gcc/x86_64-suse-linux/7/../../../../lib64/libpthread.so: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
make[2]: *** [examples/CMakeFiles/step-59.debug.dir/build.make:109: bin/step-59.debug] Error 1
make[1]: *** [CMakeFiles/Makefile2:5808: examples/CMakeFiles/step-59.debug.dir/all] Error 2
[ 87%] Built target step-52.debug
[ 87%] Built target obj_matrix_free_release
make: *** [Makefile:147: all] Error 2 

在谷歌后，得到一个方法，在DSO的cmakelist.txt文件中增加如下引用：

find_package(Threads)

并将***${CMAKE_THREAD_LIBS_INIT}***链接至执行文件：

target_link_libraries(dso_dataset dso boost_system cxsparse ${BOOST_THREAD_LIBRARY} ${LIBZIP_LIBRARY} ${Pangolin_LIBRARIES} ${OpenCV_LIBS} ${CMAKE_THREAD_LIBS_INIT})

参考帖子： https://stackoverflow.com/questions/19901934/libpthread-so-0-error-adding-symbols-dso-missing-from-command-line