Error when execute cmake

[dbfancier]

i don't known much about cmake， when i excute "cd build && cmake .."，it shows:
-- Configuring done
CMake Error at src/overlaybd/cache/ocf_cache/CMakeLists.txt:12 (add_library):
No SOURCES given to target: ocf_lib

Can anyone help me with this problem? Thanks

[liulanzheng]

@dbfancier init submodule by : git submodule update --init

[dbfancier]

@liulanzheng
thanks a lot , your method solved my promblem