Why you should NOT use Boost git repo with CPM.cmake

[ClausKlein]

• the clone of the git repo takes to long time!
• and the boost CMake files are not really designed as modern CMake project!
• there is no central include directory!
• the boost CMake system is designed for boost developers to test there submodules
• every module lib that include an header of on other module lib depends on this lib, too if it may used as header-only lib!

bash-3.2$ find . -type d -name include | wc -l
163
bash-3.2$ grep submodule .gitmodules  | wc -l
160
bash-3.2$ 

The current CPM.cmake boost example takes about 11 min to clone the boost repo and 2 min to build all dependent libs?

The build with the boost source tar file takes to fetch and extract 2 min and the build about 10 sec!

see #304 (comment)

[ClausKlein]

here you may see, how much complicate and inefficient the build with the boot git repo is:

bash-3.2$ rm main.cpp.o
bash-3.2$ cd -
/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/cmake-build-boost-x86_64-Debug/install
bash-3.2$ ninja -v CPMExampleBoost

[0/2] /usr/local/lib/python3.10/site-packages/cmake/data/bin/cmake -P /Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/cmake-build-boost-x86_64-Debug/install/CMakeFiles/VerifyGlobs.cmake

[1/2] /usr/local/bin/ccache /Applications/Xcode.app/Contents/Developer/usr/bin/g++ -DBOOST_CHRONO_DYN_LINK
-DBOOST_CHRONO_NO_LIB -DBOOST_CONTAINER_DYN_LINK -DBOOST_CONTAINER_NO_LIB -DBOOST_CONTEXT_DYN_LINK
-DBOOST_CONTEXT_EXPORT=EXPORT -DBOOST_CONTEXT_NO_LIB -DBOOST_COROUTINES_DYN_LINK -DBOOST_COROUTINE_DYN_LINK
-DBOOST_COROUTINE_NO_LIB -DBOOST_DATE_TIME_DYN_LINK -DBOOST_DATE_TIME_NO_LIB
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/asio/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/align/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/assert/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/config/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/core/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/static_assert/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/throw_exception/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/array/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/bind/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/chrono/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/integer/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/move/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/mpl/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/predef/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/preprocessor/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/type_traits/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/utility/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/io/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/ratio/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/rational/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/system/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/variant2/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/mp11/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/winapi/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/typeof/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/coroutine/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/context/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/pool/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/smart_ptr/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/exception/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/tuple/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/date_time/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/algorithm/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/concept_check/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/function/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/type_index/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/container_hash/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/describe/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/iterator/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/conversion/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/detail/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/function_types/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/fusion/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/functional/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/optional/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/range/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/regex/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/unordered/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/lexical_cast/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/container/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/intrusive/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/numeric/conversion/include
-I/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/.cache/CPM/boost/356f0b784342cd4b87552f80beee0adb61f12ff0/libs/tokenizer/include
-g -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.1.sdk
-std=gnu++20 -MD -MT CMakeFiles/CPMExampleBoost.dir/main.cpp.o -MF CMakeFiles/CPMExampleBoost.dir/main.cpp.o.d -o
CMakeFiles/CPMExampleBoost.dir/main.cpp.o -c /Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/main.cpp

[2/2] : && /Applications/Xcode.app/Contents/Developer/usr/bin/g++ -g -isysroot
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.1.sdk -Wl,-search_paths_first
-Wl,-headerpad_max_install_names  CMakeFiles/CPMExampleBoost.dir/main.cpp.o -o CPMExampleBoost
-Wl,-rpath,/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/cmake-build-boost-x86_64-Debug/install/_deps/boost-build/libs/chrono
-Wl,-rpath,/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/cmake-build-boost-x86_64-Debug/install/_deps/boost-build/libs/coroutine
-Wl,-rpath,/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/cmake-build-boost-x86_64-Debug/install/_deps/boost-build/libs/context
-Wl,-rpath,/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/cmake-build-boost-x86_64-Debug/install/_deps/boost-build/libs/date_time
-Wl,-rpath,/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/cmake-build-boost-x86_64-Debug/install/_deps/boost-build/libs/container
_deps/boost-build/libs/chrono/libboost_chrono.1.81.0.dylib
_deps/boost-build/libs/coroutine/libboost_coroutine.1.81.0.dylib
_deps/boost-build/libs/context/libboost_context.1.81.0.dylib
_deps/boost-build/libs/date_time/libboost_date_time.1.81.0.dylib
_deps/boost-build/libs/exception/libboost_exception.a
_deps/boost-build/libs/container/libboost_container.1.81.0.dylib && :

bash-3.2$

[ClausKlein]

and this the the same with the extracted boost source tar archive and boost-cmake

bash-3.2$ ninja clean
[1/1] Cleaning all built files...
Cleaning... 2 files.
bash-3.2$ ninja -nv

[1/2] /usr/local/bin/ccache /Applications/Xcode.app/Contents/Developer/usr/bin/g++ -DBOOST_ALL_NO_LIB=1
-DBOOST_ASIO_NO_DEPRECATED -DBOOST_BIND_GLOBAL_PLACEHOLDERS -DBOOST_SYSTEM_NO_DEPRECATED -DBOOST_THREAD_PROVIDES_EXECUTORS
-DBOOST_THREAD_USES_CHRONO -DBOOST_THREAD_VERSION=5 -I/Users/clausklein/.cache/CPM/boost_1_79_0 -g -isysroot
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.1.sdk
-Wno-deprecated-declarations -std=gnu++20 -MD -MT CMakeFiles/CPMExampleAsio.dir/deferred.cpp.o -MF
CMakeFiles/CPMExampleAsio.dir/deferred.cpp.o.d -o CMakeFiles/CPMExampleAsio.dir/deferred.cpp.o -c
/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost/deferred.cpp

[2/2] : && /Applications/Xcode.app/Contents/Developer/usr/bin/g++ -g -isysroot
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.1.sdk -Wl,-search_paths_first
-Wl,-headerpad_max_install_names  CMakeFiles/CPMExampleAsio.dir/deferred.cpp.o -o CPMExampleAsio   && :

bash-3.2$ cd -
/Users/clausklein/cmake/TheLartians/CPM.cmake/examples/boost
bash-3.2$

[Arniiiii]

• the clone of the git repo takes to long time!

• and the boost CMake files are not really designed as modern CMake project!

• there is no central include directory!

• the boost CMake system is designed for boost developers to test there submodules

• every module lib that include an header of on other module lib depends on this lib, too if it may used as header-only lib!

1. Try archive from releases from boost github link. Those are really fast to download. Set at CMake FETCHCONTENT_QUIET=OFF to see how fast it happens.
2. Maybe.
3. Yes, should it be? Like there's boost asio: link . And yes, its sources are separated from other boost libs. And it's ok.
4. Maybe. Though, release archives work great.
5. idk about c++ modules much and I don't use them. If you use a boost lib like in my issue , it's got to work like expected: link specific lib to your target, and your target expected to get the specific part of boost . I'll check later if dependencies are linked too, though, as far as I remember, they were.

About installation: I'll check if it works, you say it's not, and I feel to be a newbie in all this CMake stuff to know why it's not.