[CMake] link static libraries to a share library

[Jiang Xu]

Hi All,

I am new to cmake, but I really like it after looking into it.
I am in the process to make some changes to our current make file system.
I wonder how can I archieve the following goal using cmake:

1.  The root directory is features/
2.  Under root directory, there is a set of subdirectories as: feature_1/, feature_2/, ... feature_n/
3.  Under each subdirectory, there is a CMakeList.txt to compile a static library for each feature. For example, in CMakeList.txt under feature_1 directory, it has a line to create static library target: add_library(feature_1, STATIC, ${FEATURE_1_SRCS})
4.  Under root directory, there is no source code, all it does is based on user input (command line) to go into different sub-directories to build each static libraries and try to link all of them into a shared library.

It looks like add_library command must have any source code files in it.  So I don't know how to add a shared library target and all it does is to link different static libraries, there is no source file.  Can someone please help me?

Thanks in advance.

John