Should CMake be more than just a test runner?

[Justin Bassett]

From r/cpp_review.

I think that we should use cmake as more than just a test runner. I think it should be possible to consume this library through cmake.

The expected way in modern cmake is to have scope_guard be a library, something like:

add_library(ScopeGuard INTERFACE)
add_library(ScopeGuard::ScopeGuard ALIAS ScopeGuard) # for consumption via add_subdirectory()

target_include_directories(ScopeGuard
  INTERFACE
    include # assuming we move the header file to an `include` directory
)

The tests would be behind a BUILD_TESTING check, something like this:

include(CTest)

# ...

if (BUILD_TESTING)
  find_package(Catch2 REQUIRED)
  # Test targets defined here
endif()

And we'd install the target so that it can be found via find_package(ScopeGuard) (or some other variation on the name), something like this:

include(GNUInstallDirs)

install(DIRECTORY include/
  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
)

install(TARGETS ScopeGuard
  EXPORT ScopeGuardConfig
  DESTINATION "${CMAKE_INSTALL_LIBDIR}"
)

install(EXPORT ScopeGuardConfig
  NAMESPACE
    ScopeGuard::
  DESTINATION
    "${CMAKE_INSTALL_LIBDIR}/cmake/ScopeGuard}"
)

# For versioning (e.g. find_package(ScopeGuard 1.0 REQUIRED))
include(CMakePackageConfigHelpers)

write_basic_package_version_file(
  "${CMAKE_CURRENT_BINARY_DIR}/ScopeGuardConfigVersion.cmake"
  VERSION ${PROJECT_VERSION} # requires setting the project version, of course
  COMPATIBILITY SameMajorVersion # I believe this is fully customizable
)

install(FILES
    "${CMAKE_CURRENT_BINARY_DIR}/ScopeGuardConfigVersion.cmake"
  DESTINATION
    "${CMAKE_INSTALL_LIBDIR}/cmake/ScopeGuard}"
)

See this article on cmake, connected to this example github repo.

---

In doing this, it might be easier to move the header file into an include directory.

[Ricardo Abreu]

Thanks a lot @Quincunx271 that is very helpful. I will try to do this when I find the time. Cheers.

[OvermindDL1]

In essence, if you want to do things the right CMake way, follow this online 'book' by one of the big CMake people: https://cgold.readthedocs.io/en/latest/

[Ricardo Abreu]

Thanks for the pointer @OvermindDL1. I had a browse and it will perhaps be a good resource in the future. ATM I find it still a bit embryonic (many empty sections, not very intelligible in places...). But I'll be sure to check it later on.

[OvermindDL1]

Yeah it's made by programmers and is 'relatively' new, but the information it has is good. :-)