lokinet/cmake/check_for_std_filesystem.cmake
dan dc7f3cee22 Replace cxxopts with CLI11
- Simiplifies CLI code for future modification
- filesystem library linked in cmake check_for_std_filesystem file
2023-01-06 15:04:14 -08:00

52 lines
2.1 KiB
CMake

# Figure out if we need -lstdc++fs or -lc++fs and add it to the `filesystem` interface, if needed
# (otherwise just leave it an empty interface library; linking to it will do nothing). The former
# is needed for gcc before v9, and the latter with libc++ before llvm v9. But this gets more
# complicated than just using the compiler, because clang on linux by default uses libstdc++, so
# we'll just give up and see what works.
add_library(filesystem INTERFACE)
set(filesystem_code [[
#include <filesystem>
int main() {
auto cwd = std::filesystem::current_path();
return !cwd.string().empty();
}
]])
if(CMAKE_CXX_COMPILER STREQUAL "AppleClang" AND CMAKE_OSX_DEPLOYMENT_TARGET)
# It seems that check_cxx_source_compiles doesn't respect the CMAKE_OSX_DEPLOYMENT_TARGET, so this
# check would pass on Catalina (10.15) and then later compilation would fail because you aren't
# allowed to use <filesystem> when the deployment target is anything before 10.15.
set(CMAKE_REQUIRED_FLAGS -mmacosx-version-min=${CMAKE_OSX_DEPLOYMENT_TARGET})
endif()
check_cxx_source_compiles("${filesystem_code}" filesystem_compiled)
if(filesystem_compiled)
message(STATUS "No extra link flag needed for std::filesystem")
set(filesystem_is_good 1)
else()
foreach(fslib stdc++fs c++fs)
set(CMAKE_REQUIRED_LIBRARIES -l${fslib})
check_cxx_source_compiles("${filesystem_code}" filesystem_compiled_${fslib})
if (filesystem_compiled_${fslib})
message(STATUS "Using -l${fslib} for std::filesystem support")
target_link_libraries(filesystem INTERFACE ${fslib})
set(filesystem_is_good 1)
break()
endif()
endforeach()
endif()
unset(CMAKE_REQUIRED_LIBRARIES)
if(filesystem_is_good EQUAL 1)
message(STATUS "we have std::filesystem")
else()
# Probably broken AF macos
message(STATUS "std::filesystem is not available, apparently this compiler isn't C++17 compliant; falling back to ghc::filesystem")
set(GHC_FILESYSTEM_WITH_INSTALL OFF CACHE INTERNAL "")
add_subdirectory(external/ghc-filesystem)
target_link_libraries(filesystem INTERFACE ghc_filesystem)
target_compile_definitions(filesystem INTERFACE USE_GHC_FILESYSTEM CLI11_HAS_FILESYSTEM=0)
endif()