How to generate an external library to work in the ROS as the thirdparty file?

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Dear all: Today, I generated an external library using Eclipse, but I want to make it working as the thirdparty file, which is similar as gvars or libvcd in the ethzal_ptam package, but I did not have the file like configure file in them! How to do it? Thanks!!

BTW: the whole process is below steps: 1. I generate an empty Shared Library project, and then write my class files(.h and .cpp, no main function), after compiled it, I got my library .so! 2. I copy the whole files(include the library) to the thirdparty in the ethzal_ptam, and copy the makefile from the gvars3, modify it similarly, it seems the Eclipse has make it successful, but when I use the function in that library, it could not work, how could I solve it?