Feature/use file set headers by ClausKlein · Pull Request #46 · boostorg/type_index

ClausKlein · 2026-02-12T20:53:10Z

Make `import std;` usable

Add FILE_SET HEADERS too support generic module installation

Add FILE_SET HEADERS too support generic installation

apolukhin · 2026-04-24T14:21:00Z

+# -----------------------------------------------------------------------------
+# User option: enable C++ modules
+# -----------------------------------------------------------------------------
+option(BOOST_USE_MODULES "Build Boost using C++ modules" OFF)


This differs with boostorg/conversion boostorg/conversion@d324df9#diff-1e7de1ae2d059d21e1dd75d5812d5a34b0222cef273b7c3a2af62eb747f9d20a

Is that OK? Is there any conflict with https://github.com/boostorg/cmake/pull/105/changes#diff-362ae3918cd3ea347acb8663e39d697af2ec828794c33494e747ee3249dbde73R307 ?

apolukhin · 2026-04-24T14:22:48Z

+
+    # Ensure CMAKE_CXX_STANDARD is set for module detection
+    if(NOT DEFINED CMAKE_CXX_STANDARD)
+        set(CMAKE_CXX_STANDARD 20)


Is it right to set this variable from CMakeLists? Can we stick to using feature flags only?

apolukhin · 2026-04-24T14:23:23Z

    add_library(boost_type_index INTERFACE)
+
+    # If modules are disabled, require C++17 for headers
+    target_compile_features(boost_type_index INTERFACE cxx_std_17)


cxx_std_11
Library supports C++11

apolukhin · 2026-04-24T14:25:26Z

+
+    # Verify interface headers only at top level
+    if(PROJECT_IS_TOP_LEVEL)
+        set(CMAKE_VERIFY_INTERFACE_HEADER_SETS ON)


According to https://cmake.org/cmake/help/latest/variable/CMAKE_VERIFY_INTERFACE_HEADER_SETS.html#variable:CMAKE_VERIFY_INTERFACE_HEADER_SETS

Projects should not normally set this variable, it is intended as a developer control to be set on the [cmake(1)](https://cmake.org/cmake/help/latest/manual/cmake.1.html#manual:cmake(1)) command line or other equivalent methods

Maybe we should set this variable in CI only?

apolukhin · 2026-04-24T14:26:02Z

+                TYPE HEADERS
+                BASE_DIRS include
+                FILES
+                    include/boost/type_index.hpp


How about searching the files via GLOB?

apolukhin · 2026-04-24T14:28:26Z

    target_link_libraries(boost_type_index_module_usage_mu PRIVATE Boost::type_index)
    add_test(NAME boost_type_index_module_usage_mu COMMAND boost_type_index_module_usage_mu)
+else()
+    list(APPEND RUN_TESTS_SOURCES


Why is it in the else now?

apolukhin · 2026-04-24T14:30:22Z


-#ifndef BOOST_TYPE_INDEX_USE_STD_MODULE
+#ifdef BOOST_TYPE_INDEX_USE_STD_MODULE
+import std;


Looks like import std; should not be used in global module fragment https://eel.is/c++draft/module#global.frag-1

apolukhin · 2026-05-22T15:09:26Z

@ClausKlein please check the current develop branch. I think the issue should have been fixed by now

ClausKlein · 2026-05-25T08:40:45Z

@ClausKlein please check the current develop branch. I think the issue should have been fixed by now

bash-5.3$ CXX=clang++ gmake 
cmake --version
cmake version 4.3.2

CMake suite maintained and supported by Kitware (kitware.com/cmake).
cmake -S . -B build -G Ninja \
 -D CMAKE_CXX_STDLIB_MODULES_JSON=/usr/local/Cellar/llvm/22.1.6/lib/c++/libc++.modules.json \
 -D CMAKE_CXX_STANDARD=23 -D CMAKE_CXX_EXTENSIONS=YES -D CMAKE_CXX_STANDARD_REQUIRED=YES \
 -D CMAKE_CXX_MODULE_STD=YES \
 -D BOOST_USE_MODULES=YES \
 -D BUILD_TESTING=YES \
 -D CMAKE_BUILD_TYPE=Release \
 -D CMAKE_INSTALL_MESSAGE=LAZY \
 -D CMAKE_SKIP_INSTALL_RULES=NO \
 --log-level=VERBOSE --fresh \
 # --trace-expand --trace-source=use-fetch-content.cmake \
 # --debug-find-pkg=GTest
-- The CXX compiler identification is Clang 22.1.6
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/local/Cellar/llvm/22.1.6/bin/clang++ - skipped
-- Detecting CXX compile features
CMake Warning (dev) at /usr/local/share/cmake/Modules/Compiler/CMakeCommonCompilerMacros.cmake:226 (cmake_language):
  CMake's support for `import std;` in C++23 and newer is experimental.  It
  is meant only for experimentation and feedback to CMake developers.
Call Stack (most recent call first):
  /usr/local/share/cmake/Modules/CMakeDetermineCompilerSupport.cmake:110 (cmake_cxx_find_modules_json)
  /usr/local/share/cmake/Modules/CMakeTestCXXCompiler.cmake:83 (CMAKE_DETERMINE_COMPILER_SUPPORT)
  CMakeLists.txt:9 (project)
This warning is for project developers.  Use -Wno-dev to suppress it.

-- Detecting CXX compile features - done
-- Using `import std;`
-- Configuring done (1.7s)
-- Generating done (0.1s)

bash-5.3$ ninja -C build/ all -v
ninja: Entering directory `build/'
[0/2] /usr/local/bin/cmake -P /Users/clausklein/Workspace/cpp/boost-git/libs/type_index/test/cmake_subdir_test/build/CMakeFiles/VerifyGlobs.cmake
[1/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/CXX.dd.rsp
FAILED: [code=1] boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/CXX.dd boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/CXXModules.json boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/Users/clausklein/Workspace/cpp/boost-git/libs/type_index/modules/boost_type_index.cppm.o.modmap 
/usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/boost_type_index_user_defined_typeinfo.dir/CXX.dd.rsp
CMake Error: Circular dependency detected in the C++ module import graph. See modules named: "boost.type_index"
[2/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_inheritance_example.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_inheritance_example.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_inheritance_example.dir/CXX.dd.rsp
[3/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_demangled_names_example.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_demangled_names_example.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_demangled_names_example.dir/CXX.dd.rsp
[4/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_constexpr14_sort_check_example.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_constexpr14_sort_check_example.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_constexpr14_sort_check_example.dir/CXX.dd.rsp
[5/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_exact_types_match_example.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_exact_types_match_example.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_exact_types_match_example.dir/CXX.dd.rsp
[6/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_ctti_alignment_test.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_ctti_alignment_test.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_ctti_alignment_test.dir/CXX.dd.rsp
[7/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_runtime_cast_example.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_runtime_cast_example.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_runtime_cast_example.dir/CXX.dd.rsp
[8/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_table_of_names_example.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_table_of_names_example.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_table_of_names_example.dir/CXX.dd.rsp
[9/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_constexpr14_namespace_check_example.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_constexpr14_namespace_check_example.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_constexpr14_namespace_check_example.dir/CXX.dd.rsp
[10/65] /usr/local/bin/cmake -E cmake_ninja_dyndep --tdi=boostorg/type_index/test/CMakeFiles/type_index_registry_example.dir/CXXDependInfo.json --lang=CXX --modmapfmt=clang --dd=boostorg/type_index/test/CMakeFiles/type_index_registry_example.dir/CXX.dd @boostorg/type_index/test/CMakeFiles/type_index_registry_example.dir/CXX.dd.rsp
[11/65] ccache /usr/local/Cellar/llvm/22.1.6/bin/clang++  -I/usr/local/Cellar/llvm/22.1.6/share/libc++/v1 -stdlib=libc++ --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -O3 -DNDEBUG -std=gnu++23 -MD -MT CMakeFiles/__cmake_cxx_std_23.dir/usr/local/Cellar/llvm/22.1.6/share/libc++/v1/std.compat.cppm.o -MF CMakeFiles/__cmake_cxx_std_23.dir/usr/local/Cellar/llvm/22.1.6/share/libc++/v1/std.compat.cppm.o.d @CMakeFiles/__cmake_cxx_std_23.dir/usr/local/Cellar/llvm/22.1.6/share/libc++/v1/std.compat.cppm.o.modmap -o CMakeFiles/__cmake_cxx_std_23.dir/usr/local/Cellar/llvm/22.1.6/share/libc++/v1/std.compat.cppm.o -c /usr/local/Cellar/llvm/22.1.6/share/libc++/v1/std.compat.cppm
/usr/local/Cellar/llvm/22.1.6/share/libc++/v1/std.compat.cppm:83:15: warning: 'std' is a reserved name for a module [-Wreserved-module-identifier]
   83 | export module std.compat;
      |               ^
1 warning generated.
ninja: build stopped: subcommand failed.
bash-5.3$

ClausKlein added 2 commits February 12, 2026 14:18

Make import std; usable

b018ce4

Add FILE_SET HEADERS too support generic installation

Prevent use of FILE_SET w/o modules

dd6bf2f

ClausKlein mentioned this pull request Feb 12, 2026

Make import std; usable boostorg/any#40

Open

1 task

ClausKlein added 4 commits February 12, 2026 22:06

Fix yamllint issue

4480968

Fix typo

1568a4b

fix: Add missing keyword

b8d7601

Always use FILE_SET HEADERS if possible

804dd97

apolukhin reviewed Apr 24, 2026

View reviewed changes

Update to cmake v4.3

1ee819f

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Feature/use file set headers#46

Feature/use file set headers#46
ClausKlein wants to merge 7 commits into
boostorg:developfrom
ClausKlein:feature/use-file_set-headers

ClausKlein commented Feb 12, 2026

Uh oh!

apolukhin Apr 24, 2026 •

edited

Loading

Uh oh!

apolukhin Apr 24, 2026 •

edited

Loading

Uh oh!

apolukhin Apr 24, 2026 •

edited

Loading

Uh oh!

apolukhin Apr 24, 2026 •

edited

Loading

Uh oh!

apolukhin Apr 24, 2026 •

edited

Loading

Uh oh!

apolukhin Apr 24, 2026 •

edited

Loading

Uh oh!

apolukhin Apr 24, 2026 •

edited

Loading

Uh oh!

apolukhin commented May 22, 2026

Uh oh!

ClausKlein commented May 25, 2026 •

edited

Loading

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Conversation

ClausKlein commented Feb 12, 2026

Make import std; usable

Uh oh!

apolukhin Apr 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

apolukhin Apr 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

apolukhin Apr 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

apolukhin Apr 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

apolukhin Apr 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

apolukhin Apr 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

apolukhin Apr 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

apolukhin commented May 22, 2026

Uh oh!

ClausKlein commented May 25, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Make `import std;` usable

apolukhin Apr 24, 2026 •

edited

Loading

apolukhin Apr 24, 2026 •

edited

Loading

apolukhin Apr 24, 2026 •

edited

Loading

apolukhin Apr 24, 2026 •

edited

Loading

apolukhin Apr 24, 2026 •

edited

Loading

apolukhin Apr 24, 2026 •

edited

Loading

apolukhin Apr 24, 2026 •

edited

Loading

ClausKlein commented May 25, 2026 •

edited

Loading