project(unitybuild_c_no_unity_build C) set(srcs "") foreach(s RANGE 1 8) set(src "${CMAKE_CURRENT_BINARY_DIR}/s${s}.c") file(WRITE "${src}" "int s${s}(void) { return 0; }\n") list(APPEND srcs "${src}") endforeach() add_library(tgt SHARED ${srcs}) #These should be ignored as UNITY_BUILD is off set_target_properties(tgt PROPERTIES UNITY_BUILD_MODE GROUP) set_source_files_properties(s1.c s2.c s3.c s4.c s5.c s6.c s7.c s8.c PROPERTIES UNITY_GROUP "a" )