$ cat /tmp/src/CMakeLists.txt
cmake_min/imum_required (VERSION 3.4)
project(hello CXX)
add_library(foobar SHARED)
target_sources(foobar PRIVATE foobar.cc)
$ cat /tmp/src/foobar.cc
void myfunc() {
}
$ mkdir /tmp/build
$ cd /tmp/build
$ ~/tmp/cmake-3.4.0-Linux-x86_64/bin/cmake /tmp/src/
-- The CXX compiler identification is GNU 5.2.1
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
You have called ADD_LIBRARY for library foobar without any source files. This typically indicates a problem with your CMakeLists.txt file
-- Configuring done
-- Generating done
-- Build files have been written to: /tmp/build
$