When we use cmake to compile our program and use TARGET_LINK_LIBRARIES to link libraries we need, we have to pay attention to the order these libraries are specified.
In the following case, our program depends on the muduo_base library and muduo_base library depends on pthread, then we have to ensure pthread is after muduo_base:1
TARGET_LINK_LIBRARIES(${PROJECT_NAME} ${MUDUO_NET_LIBRARY} ${MUDUO_BASE_LIBRARY} pthread)
Otherwise, we would get a link error if we specify like this:1
TARGET_LINK_LIBRARIES(${PROJECT_NAME} pthread ${MUDUO_NET_LIBRARY} ${MUDUO_BASE_LIBRARY})