Library linking not working when CMake single build - cmake

Question

using CMake I want to build in each directory A, B, and C.
The project structure is as follows:
.
├── A
│   ├── CMakeLists.txt
│   └── src
│   └── a.cpp
├── B
│   ├── CMakeLists.txt
│   └── src
│   └── b.cpp
├── common
│   ├── CMakeLists.txt
│   ├── include
│   │   ├── common.h
│   └── src
│   └── common.cpp
└── C
├── CMakeLists.txt
└── src
└── c.cpp
Create a library in the Common directory and install the created library.
common/CmakeLists.txt :
set(COMMON_LIB_NAME CommonTemp)
set(SRC_CODE
${CMAKE_CURRENT_SOURCE_DIR}/include/common.h
${CMAKE_CURRENT_SOURCE_DIR}/src/common.cpp
)
add_library (${COMMON_LIB_NAME} SHARED ${SRC_CODE})
install(TARGETS ${COMMON_LIB_NAME} DESTINATION ~/tempDir/lib)
I want to link the generated library to directory A.
a.cpp requires common.h.
A/CMakeLists.txt:
ADD_EXECUTABLE(ServiceA src/a.cpp)
target_include_directories (
ServiceA PUBLIC
include
)
target_sources (
ServiceA PRIVATE
src/a.cpp
)
target_link_libraries(
ServiceA PUBLIC
${COMMON_LIB_NAME} #### Location considered to be a problem
)
install(TARGETS ServiceA DESTINATION ~/tempDir/bin/A)
An error message occurs saying that common.h cannot be included.
My guess is that the ${COMMON_LIB_NAME} variable is defined in CMakeLists.txt in another directory, so it is expected that it cannot be linked.
But even if I put CommonTemp , the value of the variable, it says that common.h cannot be found.
How can I link library links even if I build CMake individually in each directory?

Answer 1

In common/CmakeLists.txt.
You need to include the headers in target_include_directores.
target_include_directories(
${COMMON_LIB_NAME} PUBLIC
${CMAKE_CURRENT_SOURCE_DIR}/include
)
No need to mention it in add_library
In A/CMakeLists.txt. Include path is not correct.
target_include_directories(
ServiceA PUBLIC
${CMAKE_CURRENT_SOURCE_DIR}/<path to common>/include
)
For linking the library you have to mention the correct library path otherwise it will fail
target_link_libraries(
ServiceA PUBLIC
${COMMON_LIB_NAME} ${CMAKE_CURRENT_SOURCE_DIR}/<path to tempDir>/lib
)