Feature/module by ClausKlein · Pull Request #5 · ClausKlein/asio

ClausKlein · 2026-03-01T12:10:46Z

e049443 Feat: Modernise CMakeLists.txt to build and install CXX_MODULE asio the Daniela's way

…e linkage!

Changes: - Change 'static const' to 'inline const' for ssl_category and stream_category - Add optional SSL support via ASIO_ENABLE_SSL CMake option (default: OFF) - Resolves 'cannot export symbol with internal linkage' compilation error The inline specifier ensures external linkage while maintaining semantics.

- Fix typo in asio-gmf.h: 'openssl / conf.h' -> 'openssl/conf.h' - Add SYSTEM keyword for OpenSSL include directories - Change ASIO_ENABLE_SSL default to ON - Add detailed logging for OpenSSL paths

Be more verbose on CI workflow cmake --preset

ClausKlein · 2026-03-12T21:04:06Z

hey @ClausKlein, I pushed a few updates to the PR. when you have a chance, could you take a look and let me know what you think? happy to iterate further if needed.

@ecoezen I like the CMakeWorkflowPreset, but some of the Warnings are too much at the moment!
see https://learn.microsoft.com/en-us/cpp/build/reference/sdl-enable-additional-security-checks?view=msvc-180

After adding more examples and unit tests, I found a lot of deprecated interfaces used there!

Too the round trip test does not work on CI, I will try to fix it next week.

The windows preset flags are to pedantic yet.

ecoezen · 2026-03-12T21:22:26Z

hey @ClausKlein, I pushed a few updates to the PR. when you have a chance, could you take a look and let me know what you think? happy to iterate further if needed.

@ecoezen I like the CMakeWorkflowPreset, but some of the Warnings are too much at the moment!

After adding more examples and unit tests, I found a lot of deprecated interfaces used there!

Too the round trip test does not work on CI, I will try to fix it next week.

hey. i'll also look at this again tomorrow and this weekend.

are we porting tests to modules as well @ClausKlein ? i mean we should imo as its the only way to see modules are actually working, but curious how much detail implementations leaked to the tests... (I'll try it anyway)

please update checklist in the head comment if there is any other additional requirements to be covered. i'll spare some time for this.

include/asio/detail/std/version.hpp

GNUmakefile

DanielaE · 2026-03-15T17:36:03Z

@ClausKlein Maybe you have noticed my rebasement of feature branch 'module' to current Asio 1.38, plus a new branch 'module-next' living on top of Asio 'trunk'

Only for Windows and APPLE now Make some timer test faster, but not too fast

ClausKlein · 2026-03-16T09:40:06Z

@ClausKlein Maybe you have noticed my rebasement of feature branch 'module' to current Asio 1.38, plus a new branch 'module-next' living on top of Asio 'trunk'

Is it conform to the current concept C++20 modules in Boost ?

It seems not?

bash-5.3$ CXX=g++ ~/.local/bin/cmake -S . -B build --fresh -D CMAKE_CXX_STANDARD=23
-- The CXX compiler identification is GNU 15.2.0
-- Checking whether CXX compiler has -isysroot
-- Checking whether CXX compiler has -isysroot - yes
-- Checking whether CXX compiler supports OSX deployment target flag
-- Checking whether CXX compiler supports OSX deployment target flag - yes
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/local/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done (1.2s)
-- Generating done (0.0s)
-- Build files have been written to: /Users/clausklein/Workspace/cpp/asio/build
bash-5.3$ ninja -C build libasio.a -v -j 1
ninja: Entering directory `build'
[1/4] /usr/local/bin/g++  -I/Users/clausklein/Workspace/cpp/asio/include -std=c++23 -E -x c++ /Users/clausklein/Workspace/cpp/asio/module/asio.ixx -MT CMakeFiles/asio.dir/module/asio.ixx.o.ddi -MD -MF CMakeFiles/asio.dir/module/asio.ixx.o.ddi.d -fmodules-ts -fdeps-file=CMakeFiles/asio.dir/module/asio.ixx.o.ddi -fdeps-target=CMakeFiles/asio.dir/module/asio.ixx.o -fdeps-format=p1689r5 -o CMakeFiles/asio.dir/module/asio.ixx.o.ddi.i
[2/4] /Users/clausklein/.local/bin/cmake -E cmake_ninja_dyndep --tdi=CMakeFiles/asio.dir/CXXDependInfo.json --lang=CXX --modmapfmt=gcc --dd=CMakeFiles/asio.dir/CXX.dd @CMakeFiles/asio.dir/CXX.dd.rsp
[3/4] ccache /usr/local/bin/g++  -I/Users/clausklein/Workspace/cpp/asio/include -std=c++23 -MD -MT CMakeFiles/asio.dir/module/asio.ixx.o -MF CMakeFiles/asio.dir/module/asio.ixx.o.d -fmodules-ts -fmodule-mapper=CMakeFiles/asio.dir/module/asio.ixx.o.modmap -MD -fdeps-format=p1689r5 -x c++ -o CMakeFiles/asio.dir/module/asio.ixx.o -c /Users/clausklein/Workspace/cpp/asio/module/asio.ixx
FAILED: [code=1] CMakeFiles/asio.dir/module/asio.ixx.o CMakeFiles/asio.dir/asio.gcm 
ccache /usr/local/bin/g++  -I/Users/clausklein/Workspace/cpp/asio/include -std=c++23 -MD -MT CMakeFiles/asio.dir/module/asio.ixx.o -MF CMakeFiles/asio.dir/module/asio.ixx.o.d -fmodules-ts -fmodule-mapper=CMakeFiles/asio.dir/module/asio.ixx.o.modmap -MD -fdeps-format=p1689r5 -x c++ -o CMakeFiles/asio.dir/module/asio.ixx.o -c /Users/clausklein/Workspace/cpp/asio/module/asio.ixx
In file included from /Users/clausklein/Workspace/cpp/asio/module/asio-gmf.h:23,
                 from /Users/clausklein/Workspace/cpp/asio/module/asio.ixx:6:
/Users/clausklein/Workspace/cpp/asio/include/asio/detail/config.hpp:1658:36: error: conflicting declaration of 'void* asio::detail::asio_detail_posix_thread_function(void*)' in module 'asio'
 1658 | # define ASIO_VERSIONED_NAME(name) asio_ ## name
      |                                    ^~~~~
/Users/clausklein/Workspace/cpp/asio/include/asio/detail/posix_thread.hpp:93:16: note: in expansion of macro 'ASIO_VERSIONED_NAME'
   93 |   friend void* ASIO_VERSIONED_NAME(detail_posix_thread_function)(
      |                ^~~~~~~~~~~~~~~~~~~
/Users/clausklein/Workspace/cpp/asio/include/asio/detail/config.hpp:1658:36: note: previously declared in global module
 1658 | # define ASIO_VERSIONED_NAME(name) asio_ ## name
      |                                    ^~~~~
/Users/clausklein/Workspace/cpp/asio/include/asio/detail/posix_thread.hpp:34:19: note: in expansion of macro 'ASIO_VERSIONED_NAME'
   34 |   ASIO_DECL void* ASIO_VERSIONED_NAME(detail_posix_thread_function)(
      |                   ^~~~~~~~~~~~~~~~~~~
/Users/clausklein/Workspace/cpp/asio/module/asio.ixx:56:1: sorry, unimplemented: private module fragment
   56 | module :private;
      | ^~~~~~
In file included from /Users/clausklein/Workspace/cpp/asio/include/asio/impl/src.hpp:53,
                 from /Users/clausklein/Workspace/cpp/asio/module/asio.ixx:58:
/Users/clausklein/Workspace/cpp/asio/include/asio/detail/impl/posix_thread.ipp: In function 'void* asio::detail::asio_detail_posix_thread_function(void*)':
/Users/clausklein/Workspace/cpp/asio/include/asio/detail/impl/posix_thread.ipp:74:29: error: 'class asio::detail::posix_thread::func_base' is private within this context
   74 |   static_cast<posix_thread::func_base*>(arg)->run();
      |                             ^~~~~~~~~
In file included from /Users/clausklein/Workspace/cpp/asio/include/asio/detail/thread.hpp:23,
                 from /Users/clausklein/Workspace/cpp/asio/include/asio/detail/scheduler.hpp:28,
                 from /Users/clausklein/Workspace/cpp/asio/include/asio/io_context.hpp:41,
                 from /Users/clausklein/Workspace/cpp/asio/include/asio/detail/io_object_impl.hpp:23,
                 from /Users/clausklein/Workspace/cpp/asio/include/asio/basic_socket.hpp:23,
                 from /Users/clausklein/Workspace/cpp/asio/include/asio/basic_datagram_socket.hpp:20,
                 from /Users/clausklein/Workspace/cpp/asio/include/asio.hpp:30,
                 from /Users/clausklein/Workspace/cpp/asio/module/asio.ixx:23:
/Users/clausklein/Workspace/cpp/asio/include/asio/detail/posix_thread.hpp:96:9: note: declared private here
   96 |   class func_base
      |         ^~~~~~~~~
ninja: build stopped: subcommand failed.
bash-5.3$ git status
On branch feature/module-next
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	modified:   CMakeLists.txt

no changes added to commit (use "git add" and/or "git commit -a")
bash-5.3$

ClausKlein · 2026-03-17T10:57:15Z

@ecoezen I struggle with Linux-ggc-Release docker builds:

/root/.local/bin/cmake  --preset linux-gcc -D CMAKE_CXX_STANDARD=26 \
	-D ASIO_IMPORT_STD=ON \
	-D ASIO_ENABLE_SSL=OFF \
	--fresh --log-level=VERBOSE -Wdev
# -D CMAKE_CXX_STDLIB_MODULES_JSON= \
/root/.local/bin/cmake  --workflow --preset linux-gcc-release
root@b40851a7588d:/home/builder/workdir# 

root@b40851a7588d:/home/builder/workdir/build/linux-gcc# ~/.local/bin/ctest --rerun-failed --verbose -C Release
UpdateCTestConfiguration  from :/home/builder/workdir/build/linux-gcc/DartConfiguration.tcl
Test project /home/builder/workdir/build/linux-gcc
Constructing a list of tests
Done constructing a list of tests
Updating test list for fixtures
Added 0 tests to meet fixture requirements
Checking test dependency graph...
Checking test dependency graph end
test 96
    Start 96: find-package-test

96: Test command: /root/.local/share/pipx/venvs/cmake/lib/python3.12/site-packages/cmake/data/bin/ctest "--output-on-failure" "-C" "Release" "--build-and-test" "/home/builder/workdir/src/examples" "/home/builder/workdir/build/linux-gcc/src/tests/unit/find-package-test" "--build-generator" "Ninja Multi-Config" "--build-makeprogram" "/usr/bin/ninja" "--build-options" "-D ASIO_IMPORT_STD=TRUE" "-D CMAKE_BUILD_TYPE=Release" "-D CMAKE_BUILD_RPATH=/opt/gcc-16/lib64" "-D CMAKE_CXX_COMPILER=/usr/bin/g++" "-D CMAKE_CXX_EXTENSIONS=TRUE" "-D CMAKE_CXX_SCAN_FOR_MODULES=TRUE" "-D CMAKE_CXX_STANDARD=23" "-D CMAKE_CXX_STANDARD_REQUIRED=TRUE" "-D CMAKE_CXX_STDLIB_MODULES_JSON=/opt/gcc-16/lib64/libstdc++.modules.json" "-D CMAKE_PREFIX_PATH=/home/builder/workdir/build/linux-gcc/stagedir"
96: Working Directory: /home/builder/workdir/build/linux-gcc/src/tests/unit
96: Test timeout computed to be: 10000000
96: Internal cmake changing into directory: /home/builder/workdir/build/linux-gcc/src/tests/unit/find-package-test
96: ======== CMake output     ======
96: CMAKE_CXX_STDLIB_MODULES_JSON: /opt/gcc-16/lib64/libstdc++.modules.json
96: Build asio with target PROPERTY CXX_MODULE_STD ON
96: Configuring done (0.0s)
96: CMake Warning (dev) in CMakeLists.txt:
96:   CMake's support for `import std;` in C++23 and newer is experimental.  It
96:   is meant only for experimentation and feedback to CMake developers.
96: This warning is for project developers.  Use -Wno-dev to suppress it.
96: 
96: Generating done (0.1s)
96: Build files have been written to: /home/builder/workdir/build/linux-gcc/src/tests/unit/find-package-test
96: ======== End CMake output ======
96: Change Dir: '/home/builder/workdir/build/linux-gcc/src/tests/unit/find-package-test'
96: 
96: Run Clean Command: /usr/bin/ninja -f build-Release.ninja clean
96: [1/1] Cleaning all built files...
96: Cleaning... 42 files.
96: 
96: Run Build Command(s): /usr/bin/ninja -f build-Release.ninja
96: [1/23] Scanning /home/builder/workdir/src/examples/interface_part.cppm for CXX dependencies
96: [2/23] Scanning /home/builder/workdir/src/examples/User.cpp for CXX dependencies
96: [3/23] Scanning /home/builder/workdir/src/examples/M.cppm for CXX dependencies
96: [4/23] Scanning /opt/gcc-16/include/c++/16.0.1/bits/std.compat.cc for CXX dependencies
96: [5/23] Scanning /home/builder/workdir/src/examples/impl_part.cpp for CXX dependencies
96: [6/23] Scanning /home/builder/workdir/src/examples/Impl.cpp for CXX dependencies
96: [7/23] Generating CXX dyndep file CMakeFiles/M.dir/Release/CXX.dd
96: [8/23] Generating CXX dyndep file CMakeFiles/example.User.dir/Release/CXX.dd
96: [9/23] Building CXX object CMakeFiles/M.dir/Release/interface_part.cppm.o
96: [10/23] Building CXX object CMakeFiles/M.dir/Release/M.cppm.o
96: [11/23] Building CXX object CMakeFiles/example.User.dir/Release/User.cpp.o
96: [12/23] Scanning /opt/gcc-16/include/c++/16.0.1/bits/std.cc for CXX dependencies
96: [13/23] Generating CXX dyndep file 'CMakeFiles/__CMAKE__CXX23@synth_f96929115e2d.dir/Release/CXX.dd'
96: [14/23] Building CXX object CMakeFiles/M.dir/Release/impl_part.cpp.o
96: [15/23] Building CXX object CMakeFiles/M.dir/Release/Impl.cpp.o
96: [16/23] Linking CXX static library Release/libM.a
96: [17/23] Linking CXX executable Release/example.User
96: [18/23] Scanning /home/builder/workdir/build/linux-gcc/stagedir/lib/cmake/asio-1.36.0/modules/asio.ixx for CXX dependencies
96: [19/23] Generating CXX dyndep file 'CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/CXX.dd'
96: [20/23] Scanning /home/builder/workdir/src/examples/cpp20/invocation/completion_executor.cpp for CXX dependencies
96: [21/23] Generating CXX dyndep file CMakeFiles/example.completion_executor.dir/Release/CXX.dd
96: [22/25] Building CXX object 'CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi'
96: FAILED: CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi 
96: /usr/bin/g++ -DASIO_DISABLE_BOOST_CONTEXT_FIBER -DASIO_HAS_IMPORT_STD -DASIO_STANDALONE -DCMAKE_INTDIR=\"Release\" -isystem /home/builder/workdir/build/linux-gcc/stagedir/include/asio-1.36.0 -O3 -DNDEBUG -std=gnu++23 -fmodule-only -MD -MT 'CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi' -MF CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi.d -fmodules-ts -fmodule-mapper=CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi.modmap -MD -fdeps-format=p1689r5 -x c++ -o 'CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi' -c /home/builder/workdir/build/linux-gcc/stagedir/lib/cmake/asio-1.36.0/modules/asio.ixx
96: /home/builder/workdir/build/linux-gcc/stagedir/lib/cmake/asio-1.36.0/modules/asio.ixx:11:1: fatal error: unknown compiled module interface: no such module
96:    11 | import std;
96:       | ^~~~~~
96: compilation terminated.
96: [23/25] Building CXX object 'CMakeFiles/__CMAKE__CXX23@synth_f96929115e2d.dir/Release/7a02772df09c.bmi'
96: ninja: build stopped: subcommand failed.
96: 
1/1 Test #96: find-package-test ................***Failed    6.45 sec

0% tests passed, 1 tests failed out of 1

Total Test time (real) =   6.46 sec

The following tests FAILED:
	 96 - find-package-test (Failed)
Errors while running CTest
Output from these tests are in: /home/builder/workdir/build/linux-gcc/Testing/Temporary/LastTest.log
Use "--rerun-failed --output-on-failure" to re-run the failed cases verbosely.
root@b40851a7588d:/home/builder/workdir/build/linux-gcc#

This tests if the targets are usable from the install directory NOTE: should be work with Debug and Release builds! CK Round trip test works only yet in Debug on Linux? Use clang-format with ColumnLimit: 99

ecoezen · 2026-03-17T15:01:44Z

@ecoezen I struggle with Linux-ggc-Release docker builds:

/root/.local/bin/cmake  --preset linux-gcc -D CMAKE_CXX_STANDARD=26 \
	-D ASIO_IMPORT_STD=ON \
	-D ASIO_ENABLE_SSL=OFF \
	--fresh --log-level=VERBOSE -Wdev
# -D CMAKE_CXX_STDLIB_MODULES_JSON= \
/root/.local/bin/cmake  --workflow --preset linux-gcc-release
root@b40851a7588d:/home/builder/workdir# 

root@b40851a7588d:/home/builder/workdir/build/linux-gcc# ~/.local/bin/ctest --rerun-failed --verbose -C Release
UpdateCTestConfiguration  from :/home/builder/workdir/build/linux-gcc/DartConfiguration.tcl
Test project /home/builder/workdir/build/linux-gcc
Constructing a list of tests
Done constructing a list of tests
Updating test list for fixtures
Added 0 tests to meet fixture requirements
Checking test dependency graph...
Checking test dependency graph end
test 96
    Start 96: find-package-test

96: Test command: /root/.local/share/pipx/venvs/cmake/lib/python3.12/site-packages/cmake/data/bin/ctest "--output-on-failure" "-C" "Release" "--build-and-test" "/home/builder/workdir/src/examples" "/home/builder/workdir/build/linux-gcc/src/tests/unit/find-package-test" "--build-generator" "Ninja Multi-Config" "--build-makeprogram" "/usr/bin/ninja" "--build-options" "-D ASIO_IMPORT_STD=TRUE" "-D CMAKE_BUILD_TYPE=Release" "-D CMAKE_BUILD_RPATH=/opt/gcc-16/lib64" "-D CMAKE_CXX_COMPILER=/usr/bin/g++" "-D CMAKE_CXX_EXTENSIONS=TRUE" "-D CMAKE_CXX_SCAN_FOR_MODULES=TRUE" "-D CMAKE_CXX_STANDARD=23" "-D CMAKE_CXX_STANDARD_REQUIRED=TRUE" "-D CMAKE_CXX_STDLIB_MODULES_JSON=/opt/gcc-16/lib64/libstdc++.modules.json" "-D CMAKE_PREFIX_PATH=/home/builder/workdir/build/linux-gcc/stagedir"
96: Working Directory: /home/builder/workdir/build/linux-gcc/src/tests/unit
96: Test timeout computed to be: 10000000
96: Internal cmake changing into directory: /home/builder/workdir/build/linux-gcc/src/tests/unit/find-package-test
96: ======== CMake output     ======
96: CMAKE_CXX_STDLIB_MODULES_JSON: /opt/gcc-16/lib64/libstdc++.modules.json
96: Build asio with target PROPERTY CXX_MODULE_STD ON
96: Configuring done (0.0s)
96: CMake Warning (dev) in CMakeLists.txt:
96:   CMake's support for `import std;` in C++23 and newer is experimental.  It
96:   is meant only for experimentation and feedback to CMake developers.
96: This warning is for project developers.  Use -Wno-dev to suppress it.
96: 
96: Generating done (0.1s)
96: Build files have been written to: /home/builder/workdir/build/linux-gcc/src/tests/unit/find-package-test
96: ======== End CMake output ======
96: Change Dir: '/home/builder/workdir/build/linux-gcc/src/tests/unit/find-package-test'
96: 
96: Run Clean Command: /usr/bin/ninja -f build-Release.ninja clean
96: [1/1] Cleaning all built files...
96: Cleaning... 42 files.
96: 
96: Run Build Command(s): /usr/bin/ninja -f build-Release.ninja
96: [1/23] Scanning /home/builder/workdir/src/examples/interface_part.cppm for CXX dependencies
96: [2/23] Scanning /home/builder/workdir/src/examples/User.cpp for CXX dependencies
96: [3/23] Scanning /home/builder/workdir/src/examples/M.cppm for CXX dependencies
96: [4/23] Scanning /opt/gcc-16/include/c++/16.0.1/bits/std.compat.cc for CXX dependencies
96: [5/23] Scanning /home/builder/workdir/src/examples/impl_part.cpp for CXX dependencies
96: [6/23] Scanning /home/builder/workdir/src/examples/Impl.cpp for CXX dependencies
96: [7/23] Generating CXX dyndep file CMakeFiles/M.dir/Release/CXX.dd
96: [8/23] Generating CXX dyndep file CMakeFiles/example.User.dir/Release/CXX.dd
96: [9/23] Building CXX object CMakeFiles/M.dir/Release/interface_part.cppm.o
96: [10/23] Building CXX object CMakeFiles/M.dir/Release/M.cppm.o
96: [11/23] Building CXX object CMakeFiles/example.User.dir/Release/User.cpp.o
96: [12/23] Scanning /opt/gcc-16/include/c++/16.0.1/bits/std.cc for CXX dependencies
96: [13/23] Generating CXX dyndep file 'CMakeFiles/__CMAKE__CXX23@synth_f96929115e2d.dir/Release/CXX.dd'
96: [14/23] Building CXX object CMakeFiles/M.dir/Release/impl_part.cpp.o
96: [15/23] Building CXX object CMakeFiles/M.dir/Release/Impl.cpp.o
96: [16/23] Linking CXX static library Release/libM.a
96: [17/23] Linking CXX executable Release/example.User
96: [18/23] Scanning /home/builder/workdir/build/linux-gcc/stagedir/lib/cmake/asio-1.36.0/modules/asio.ixx for CXX dependencies
96: [19/23] Generating CXX dyndep file 'CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/CXX.dd'
96: [20/23] Scanning /home/builder/workdir/src/examples/cpp20/invocation/completion_executor.cpp for CXX dependencies
96: [21/23] Generating CXX dyndep file CMakeFiles/example.completion_executor.dir/Release/CXX.dd
96: [22/25] Building CXX object 'CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi'
96: FAILED: CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi 
96: /usr/bin/g++ -DASIO_DISABLE_BOOST_CONTEXT_FIBER -DASIO_HAS_IMPORT_STD -DASIO_STANDALONE -DCMAKE_INTDIR=\"Release\" -isystem /home/builder/workdir/build/linux-gcc/stagedir/include/asio-1.36.0 -O3 -DNDEBUG -std=gnu++23 -fmodule-only -MD -MT 'CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi' -MF CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi.d -fmodules-ts -fmodule-mapper=CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi.modmap -MD -fdeps-format=p1689r5 -x c++ -o 'CMakeFiles/asio__asio@synth_f96929115e2d.dir/Release/7bf0e0f07b9c.bmi' -c /home/builder/workdir/build/linux-gcc/stagedir/lib/cmake/asio-1.36.0/modules/asio.ixx
96: /home/builder/workdir/build/linux-gcc/stagedir/lib/cmake/asio-1.36.0/modules/asio.ixx:11:1: fatal error: unknown compiled module interface: no such module
96:    11 | import std;
96:       | ^~~~~~
96: compilation terminated.
96: [23/25] Building CXX object 'CMakeFiles/__CMAKE__CXX23@synth_f96929115e2d.dir/Release/7a02772df09c.bmi'
96: ninja: build stopped: subcommand failed.
96: 
1/1 Test #96: find-package-test ................***Failed    6.45 sec

0% tests passed, 1 tests failed out of 1

Total Test time (real) =   6.46 sec

The following tests FAILED:
	 96 - find-package-test (Failed)
Errors while running CTest
Output from these tests are in: /home/builder/workdir/build/linux-gcc/Testing/Temporary/LastTest.log
Use "--rerun-failed --output-on-failure" to re-run the failed cases verbosely.
root@b40851a7588d:/home/builder/workdir/build/linux-gcc#

hey @ClausKlein, it seems there is a race condition due to a missing dependency link between the .bmi compilations:

[13/23] generates the CXX.dd dyndep graph for the std target.
[22/25] tries to actually build the asio .bmi and fails (fatal error: unknown module: no such module import std;).
[23/25] is the step that actually builds the std .bmi that is required for asio.bmi compilation in step 22.

it seems something is broken with modules over find_package boundaries on cmake ? which cmake version you have on your docker @ClausKlein ?

also, it is weird to see -D CMAKE_CXX_COMPILER=/usr/bin/g++ is being mixed with
-D CMAKE_CXX_STDLIB_MODULES_JSON=/opt/gcc-16/.../libstdc++.modules.json. it uses system g++ (if not symlinked to gcc 16) but not system std lib modules.

ClausKlein · 2026-03-17T17:53:37Z

it is the same docker image used on CI. And the Debug build works!

https://discourse.cmake.org/t/import-std-with-ninja-multi-config-generator-does-not-work-in-release/15561

root@b40851a7588d:/home/builder/workdir# g++ --version
g++ (GCC) 16.0.1 20260316 (experimental)
Copyright (C) 2026 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

root@b40851a7588d:/home/builder/workdir# uname -a
Linux b40851a7588d 6.12.72-linuxkit #1 SMP PREEMPT_DYNAMIC Wed Feb 25 13:22:15 UTC 2026 x86_64 x86_64 x86_64 GNU/Linux
root@b40851a7588d:/home/builder/workdir# ~/.local/bin/cmake  --version
cmake version 4.2.3

CMake suite maintained and supported by Kitware (kitware.com/cmake).
root@b40851a7588d:/home/builder/workdir# ninja --version
1.11.1
root@b40851a7588d:/home/builder/workdir# ~/.local/bin/ninja --version
bash: /root/.local/bin/ninja: No such file or directory
root@b40851a7588d:/home/builder/workdir# which ninja
/usr/bin/ninja
root@b40851a7588d:/home/builder/workdir# pipx install ninja
⚠️  Note: ninja was already on your PATH at /usr/bin/ninja
  installed package ninja 1.13.0, installed using Python 3.12.3
  These apps are now globally available
    - ninja
done! ✨ 🌟 ✨
root@b40851a7588d:/home/builder/workdir# ~/.local/bin/ninja --version
1.13.0.git.kitware.jobserver-pipe-1
root@b40851a7588d:/home/builder/workdir# g++-1
g++-13  g++-14  g++-15  g++-16  
root@b40851a7588d:/home/builder/workdir# which g++-16
/usr/bin/g++-16
root@b40851a7588d:/home/builder/workdir# ll /usr/bin/g++-16 
lrwxrwxrwx 1 root root 24 Mar 16 17:00 /usr/bin/g++-16 -> /etc/alternatives/g++-16*
root@b40851a7588d:/home/builder/workdir# ll /opt/  
cmake-latest/ gcc-15/       gcc-16/       
root@b40851a7588d:/home/builder/workdir# ll /opt/
total 20
drwxr-xr-x  1 root root 4096 Mar 16 17:00 ./
drwxr-xr-x  1 root root 4096 Mar 16 17:56 ../
drwxr-xr-x  4 root root 4096 Feb  1 03:47 cmake-latest/
drwxr-xr-x  9 root root 4096 Mar 16 05:02 gcc-15/
drwxr-xr-x 10 root root 4096 Mar 16 17:00 gcc-16/
root@b40851a7588d:/home/builder/workdir# ll /opt/*
/opt/cmake-latest:
total 16
drwxr-xr-x  4 root root 4096 Feb  1 03:47 ./
drwxr-xr-x  1 root root 4096 Mar 16 17:00 ../
drwxr-xr-x  2 root root 4096 Jan 27 16:17 bin/
drwxr-xr-x 10 root root 4096 Jan 27 16:17 share/

/opt/gcc-15:
total 36
drwxr-xr-x 9 root root 4096 Mar 16 05:02 ./
drwxr-xr-x 1 root root 4096 Mar 16 17:00 ../
drwxr-xr-x 2 root root 4096 Mar 16 05:02 bin/
drwxr-xr-x 3 root root 4096 Mar 16 05:02 include/
drwxr-xr-x 3 root root 4096 Mar 16 05:02 lib/
drwxr-xr-x 2 root root 4096 Mar 16 05:02 lib32/
drwxr-xr-x 2 root root 4096 Mar 16 05:02 lib64/
drwxr-xr-x 3 root root 4096 Mar 16 05:02 libexec/
drwxr-xr-x 6 root root 4096 Mar 16 05:02 share/

/opt/gcc-16:
total 40
drwxr-xr-x 10 root root 4096 Mar 16 17:00 ./
drwxr-xr-x  1 root root 4096 Mar 16 17:00 ../
drwxr-xr-x  2 root root 4096 Mar 16 17:00 bin/
drwxr-xr-x  3 root root 4096 Mar 16 17:00 include/
drwxr-xr-x  4 root root 4096 Mar 16 17:00 lib/
drwxr-xr-x  2 root root 4096 Mar 16 17:00 lib32/
drwxr-xr-x  2 root root 4096 Mar 16 17:00 lib64/
drwxr-xr-x  3 root root 4096 Mar 16 17:00 libexec/
drwxr-xr-x  6 root root 4096 Mar 16 17:00 share/
drwxr-xr-x  4 root root 4096 Mar 16 17:00 x86_64-pc-linux-gnu/
root@b40851a7588d:/home/builder/workdir# /opt/cmake-latest/bin/cmake --version
cmake version 4.2.3

CMake suite maintained and supported by Kitware (kitware.com/cmake).
root@b40851a7588d:/home/builder/workdir#

ecoezen · 2026-03-19T13:53:46Z

it is the same docker image used on CI. And the Debug build works!

https://discourse.cmake.org/t/import-std-with-ninja-multi-config-generator-does-not-work-in-release/15561

well, well, well... i've never though it was about ninja multi config gen, but thanks for reporting. ironically, your findings about ninja issue solve problems with one of my project's CI.

unrelated but, this whole human->cmake->generator->compiler makes the life harder for most non-corpo/non-academic projects imo. i'll eventually adopt some build tool(e.g. xmake, build2) that basicaly reduce this complexity after CPS(common package specification) finalized and implemented by build tool vendors so we can enjoy freedom with enhanced interopability...

DanielaE and others added 26 commits December 6, 2025 11:26

assumed version 1.37.0

c4b217a

assumed version 1.38.0

af74aed

Fix missing "C" linkage specifier

5c62899

Workaround for deprecated std::aligned_storage

8924506

compile as module, support CMake, create link to 'module'

4fef03a

Don't export definitions with internal linkage (e.g. 'static')

d4b1176

make TU-local entities extern

4a417e7

replace concepts emulation with requires expressions

86fc07b

add GHA to build modules

bd7954d

compiles with Clang in MSYS2 ucrt64

0052fb1

Improve CMake support

dd9f7e2

Compile with Clang in MSYS2 ucrt64

5e51704

Reorder header inclusion in GMF to keep Clang happy

2e8cade

Enable CMake 3.27

e52baf8

Fix building the module on 'pthread'-based systems: consistent langag…

232953f

…e linkage!

Include sys/epoll.h in the GMF

63ae4dc

Include sys/eventfd.h in the GMF

1915f74

drop -fchar8_t

66217b3

Support CMake 3.28 and retain support for earlier versions

9dc1786

Work around the "vtable in named module" bug in Clang 16 😱

2d71ab4

if (cond) -> if constexpr (cond) with compiletime-known condition

dad2488

fix compile issues from in-house tests

e8ab8db

pick up library customizations from the surrounding environment

d38f89a

Fix OpenSSL header include and improve CMake configuration

3c60183

- Fix typo in asio-gmf.h: 'openssl / conf.h' -> 'openssl/conf.h' - Add SYSTEM keyword for OpenSSL include directories - Change ASIO_ENABLE_SSL default to ON - Add detailed logging for OpenSSL paths

Feat: Modernize CMakeLists.txt

e049443

ClausKlein self-assigned this Mar 1, 2026

ClausKlein added 2 commits March 1, 2026 16:24

Prepare build with import std;

5627530

Check more header fix missing includes

3b8ab7a

ClausKlein mentioned this pull request Mar 1, 2026

MSVC compilation fails in header mode due to requires evaluation bug in get_completion_signatures_for_helper bemanproject/execution#227

Closed

ClausKlein force-pushed the feature/module branch from 6cc308e to a4f234c Compare March 11, 2026 22:21

Be less pedantic on UNIX, disable old examples

4b63533

Be more verbose on CI workflow cmake --preset

ClausKlein force-pushed the feature/module branch from 57b38e5 to 4b63533 Compare March 11, 2026 23:13

Make it works on APPLE with clang++

0d87cf5

ClausKlein requested review from DanielaE, camio and ednolan and removed request for DanielaE March 12, 2026 20:56

Prevent errors with deprecated interfaces on CI

e3f356c

The windows preset flags are to pedantic yet.

ClausKlein force-pushed the feature/module branch from 7d84920 to e3f356c Compare March 12, 2026 21:07

ClausKlein commented Mar 12, 2026

View reviewed changes

include/asio/detail/std/version.hpp Outdated Show resolved Hide resolved

Use clang-format for new added headers

00f7274

ClausKlein commented Mar 12, 2026

View reviewed changes

GNUmakefile Show resolved Hide resolved

ClausKlein mentioned this pull request Mar 15, 2026

g++-15 with CXX_MODULES does not compile friends bemanproject/monadics#15

Open

Try to fix round trip test on CI

db48de6

Only for Windows and APPLE now Make some timer test faster, but not too fast

ClausKlein force-pushed the feature/module branch from f88e6fb to db48de6 Compare March 16, 2026 07:42

ClausKlein requested a review from DanielaE March 16, 2026 10:08

Add round trip test for all used toolchains

c1e29c3

This tests if the targets are usable from the install directory NOTE: should be work with Debug and Release builds! CK Round trip test works only yet in Debug on Linux? Use clang-format with ColumnLimit: 99

ClausKlein force-pushed the feature/module branch from 0ce3a23 to c1e29c3 Compare March 17, 2026 11:19

Use always Ninja generator for find-package-test

035b77b

ClausKlein force-pushed the feature/module branch from 26818db to 035b77b Compare March 17, 2026 20:45

Prevent verify header errors when SSL is disabled

85d2aed

Provide feedback

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