how to include custom libraries

Hi everyone, I have a library(in C++) and I can compile and use it without ROS. It's a TCP/IP communication library. I want to listen those msgs and publish/use them in ROS. I know how to modify the cpp file to publish those msgs. But I don't know how to compile all together in ROS. So far, I found that I need to include target_link_libraries in CMakeList.txt file, but could not get it working. Let's say, my library sitting in home/ros_workspace/my_lib how should I modify the CMakeList.txt file? Thanks