CMake - get cmake variable value from the subdirectory [duplicate] - cmake

Question

This question already has an answer here:
cmake variable scope, add_subdirectory
(1 answer)
Closed 7 months ago.
I have two projects - the first one contains the second one as a subdirectory. in the second project I add the path to the my cmake modules in CMAKE_MODULE_PATH, and in the first project I add the second one using the add_subdirectory command. Then I try to include the module in the first project, but cmake saying me:
CMake Error at tests/CMakeLists.txt:7 (include):
include could not find requested file
and the CMAKE_MODULE_PATH is empty.
How I can save value of CMAKE_MODULE_PATH to then use in the first project?
that's my CMakeLists:
2nd project:
cmake_minimum_required(VERSION 3.23 FATAL_ERROR)
set(UTILS_PROJECT_NAME "utils")
set(UTILS_LIB_NAME "utils")
set(UTILS_VERSION_MAJOR 0)
set(UTILS_VERSION_MINOR 0)
set(UTILS_VERSION_PATCH 1)
set(UTILS_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
if(${CMAKE_SOURCE_DIR} STREQUAL ${UTILS_SOURCE_DIR})
set(UTILS_STANDALONE ON)
message(STATUS "utils standalone")
endif()
option(UTILS_BUILD_DOCS "Build the utils documentation" OFF)
option(UTILS_BUILD_TESTS "Guild the utils tests and examples" ${UTILS_STANDALONE})
project(${UTILS_PROJECT_NAME}
VERSION ${UTILS_VERSION_MAJOR}.${UTILS_VERSION_MINOR}.${UTILS_VERSION_PATCH}
LANGUAGES CXX
)
...
setup library target
...
if(NOT "${UTILS_SOURCE_DIR}/cmake" IN_LIST CMAKE_MODULE_PATH)
list(APPEND CMAKE_MODULE_PATH "${UTILS_SOURCE_DIR}/cmake")
endif()
if (${UTILS_BUILD_DOCS})
add_subdirectory(docs)
endif()
if(${UTILS_BUILD_TESTS})
add_subdirectory(tests)
endif()
1st project:
cmake_minimum_required(VERSION 3.23 FATAL_ERROR)
set(ENGINE_PROJECT_NAME "engine")
set(ENGINE_LIB_NAME "engine")
set(ENGINE_VERSION_MAJOR 0)
set(ENGINE_VERSION_MINOR 0)
set(ENGINE_VERSION_PATCH 1)
set(ENGINE_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
if(${CMAKE_SOURCE_DIR} STREQUAL ${ENGINE_SOURCE_DIR})
set(ENGINE_STANDALONE ON)
message(STATUS "engine standalone")
endif()
option(ENGINE_BUILD_TESTS "Build the tests and examples" ${ENGINE_STANDALONE})
project(${ENGINE_PROJECT_NAME}
VERSION ${ENGINE_VERSION_MAJOR}.${ENGINE_VERSION_MINOR}.${ENGINE_VERSION_PATCH}
LANGUAGES CXX
)
# bad way
list(APPEND CMAKE_MODULE_PATH "${ENGINE_SOURCE_DIR}/src/ext/utils/cmake")
add_subdirectory(src) # add_subdirectory(path/to/utils)
if(${ENGINE_BUILD_TESTS})
add_subdirectory(tests) # use utils cmake modules (utils_add_tests)
endif()

Answer 1

In first project, you can use set(CMAKE_MODULE_PATH "/path/to/the/second/project") to set CMAKE_MODULE_PATH, or else CMAKE_MODULE_PATH is empty by default.
Could you show more cmakefile's details for positioning problem?