To compile fmt module define FMT_MODULE

Author: ClausKlein

CMakeLists.txt

@@ -11,20 +11,37 @@ project(fmt
 
 include(cmake/variables.cmake)
 
-# XXX NO! set(CPPdefinitions FMT_ATTACH_TO_GLOBAL_MODULE)
-set(CPPdefinitions)
-
-set(CMAKE_VERIFY_INTERFACE_HEADER_SETS ${PROJECT_IS_TOP_LEVEL})
 set(CMAKE_DEBUG_POSTFIX D)
+set(CPPdefinitions)
 
-# TODO: option(FMT_SEPARATE_COMPILATION "build fmt lib too" ${PROJECT_IS_TOP_LEVEL})
-option(FMT_USE_MODULES "Export a CXX_MODULE asio if possible" ${FMT_SEPARATE_COMPILATION})
-option(FMT_IMPORT_STD "Import the CXX_MODULE std if possible" OFF)
+option(FMT_SEPARATE_COMPILATION "build fmt lib too" ${PROJECT_IS_TOP_LEVEL})
+option(FMT_USE_MODULES "Export a CXX_MODULE asio if possible" ${PROJECT_IS_TOP_LEVEL})
+# TODO: option(FMT_IMPORT_STD "Import the CXX_MODULE std if possible" ${FMT_USE_MODULES})
 
 if(FMT_IMPORT_STD)
-  set(CPPdefinitions FMT_IMPORT_STD)
+  list(APPEND CPPdefinitions FMT_IMPORT_STD)
+endif()
+
+if(FMT_USE_MODULES)
+  list(APPEND CPPdefinitions FMT_MODULE)
+  # XXX NO! list(APPEND CPPdefinitions FMT_ATTACH_TO_GLOBAL_MODULE)
+  # FIXME: add_compile_options(-Wno-reserved-module-identifier -Wno-include-angled-in-module-purview)
+
+  if(FMT_IMPORT_STD) # FIXME: clang++ only! AND $ENV{LLVM_ROOT})
+    set(CMAKE_CXX_COMPILER_IMPORT_STD 23)
+    add_compile_options(-fexperimental-library)
+    add_link_options(-lc++experimental)
+    add_compile_options(-stdlib=libc++)
+    add_link_options(-stdlib=libc++)
+
+    message(STATUS "CMAKE_CXX_COMPILER_IMPORT_STD=${CMAKE_CXX_COMPILER_IMPORT_STD}")
+  endif()
+
+  message(STATUS "CPPdefinitions=${CPPdefinitions}")
+else()
+  set(CMAKE_VERIFY_INTERFACE_HEADER_SETS ${PROJECT_IS_TOP_LEVEL})
 endif()
-#
+
 # ---- add dependency libraries ----
 
 include(cmake/CPM.cmake)
@@ -66,7 +83,6 @@ target_compile_options(fmt-header-only INTERFACE $<$<AND:$<COMPILE_LANGUAGE:CXX>
 
 if(FMT_SEPARATE_COMPILATION)
   file(GLOB_RECURSE _fmt_all_sources "${fmt_SOURCE_DIR}/src/*.cc")
-  set(_fmt_sources ${fmt_SOURCE_DIR}/src/fmt.cc)
 
   add_library(fmt)
   add_library(fmt::fmt ALIAS fmt)
@@ -79,19 +95,22 @@ if(FMT_SEPARATE_COMPILATION)
   )
 
   if(FMT_USE_MODULES)
-    target_compile_definitions(fmt PUBLIC USE_MODULES ${CPPdefinitions})
+    target_compile_definitions(fmt PUBLIC ${CPPdefinitions})
     # cmake-format: off
     target_sources(fmt PUBLIC
         FILE_SET public_modules
         TYPE CXX_MODULES
-        BASE_DIRS ${PROJECT_SOURCE_DIR}
+        BASE_DIRS
+            #NO! ${fmt_SOURCE_DIR}
+            ${PROJECT_SOURCE_DIR}/module
         FILES
+            #NO! ${_fmt_all_sources}
             ${PROJECT_SOURCE_DIR}/module/fmt.cppm
     )
     # cmake-format: on
   else()
-    target_compile_definitions(fmt PUBLIC FMT_SEPARATE_COMPILATION ${CPPdefinitions})
-    target_sources(fmt PUBLIC ${_fmt_sources})
+    target_compile_definitions(fmt PUBLIC ${CPPdefinitions})
+    target_sources(fmt PUBLIC ${_fmt_all_sources})
   endif()
 
   if(FMT_WARNINGS_AS_ERRORS AND FMT_DEVELOPER_MODE AND UNIX)

CMakePresets.json

@@ -49,8 +49,8 @@
           "This preset makes sure the project actually builds with at least the specified standard",
       "hidden": true,
       "cacheVariables": {
-        "CMAKE_CXX_EXTENSIONS": "OFF",
-        "CMAKE_CXX_STANDARD": "20",
+        "CMAKE_CXX_EXTENSIONS": "ON",
+        "CMAKE_CXX_STANDARD": "23",
         "CMAKE_CXX_STANDARD_REQUIRED": "ON"
       }
     },

GNUmakefile

@@ -8,6 +8,17 @@ MAKEFLAGS+= --warn-undefined-variables
 
 export hostSystemName=$(shell uname)
 
+ifeq (${hostSystemName},Darwin)
+  export LLVM_PREFIX:=$(shell brew --prefix llvm@19)
+  export LLVM_ROOT:=$(shell realpath ${LLVM_PREFIX})
+
+  export LDFLAGS?=-L${LLVM_ROOT}/lib/c++
+  export PATH:=${LLVM_ROOT}/bin:${PATH}
+  export CXX:=clang++
+else ifeq (${UNAME},Linux)
+  export LLVM_ROOT:=/usr/lib/llvm-19
+endif
+
 .PHONY: all check test format clean distclean
 all: .init
 	cmake --workflow --preset dev --fresh

cmake/install-rules.cmake

@@ -16,12 +16,14 @@ set(FMT_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/cmake/${_package}"
 mark_as_advanced(FMT_INSTALL_CMAKEDIR)
 
 install(TARGETS fmt-header-only EXPORT fmtTargets FILE_SET HEADERS)
-install(FILES module/fmt.cppm DESTINATION ${FMT_INSTALL_CMAKEDIR}/module)
 
 if(FMT_USE_MODULES)
   install(TARGETS fmt EXPORT fmtTargets FILE_SET public_headers FILE_SET public_modules
           DESTINATION ${FMT_INSTALL_CMAKEDIR}/module
   )
+  install(FILES ${_fmt_all_sources} DESTINATION ${FMT_INSTALL_CMAKEDIR}/module)
+else()
+  install(FILES module/fmt.cppm DESTINATION ${FMT_INSTALL_CMAKEDIR}/module)
 endif()
 
 write_basic_package_version_file("${_package}ConfigVersion.cmake" COMPATIBILITY SameMajorVersion ARCH_INDEPENDENT)

tests/header-only-test.cc

@@ -1,6 +1,6 @@
 // Header-only configuration test
 
-#ifdef FMT_USE_MODULES
+#ifdef FMT_MODULE
 import fmt;
 #else
 #  include "fmt/base.h"