compile with python 3.13t (nogil)

[subaochen]

I have installed free-threading python 3.13 following https://py-free-threading.github.io/installing_cpython/ on ubuntu 22.04(with gcc 11.04.0), with command:

conda create -n nogil --override-channels -c conda-forge python-freethreading

But compile python 3.13t with boost-1.86.0 failed, below the steps:

1, configure boost successfully:
./bootstrap.sh --with-python=/home/mydesktop/anaconda3/envs/nogil

2, compile boost failed:
./b2 --toolset=gcc --with-python include="/home/mydesktop/anaconda3/envs/nogil/include/python3.13t/" --with-thread --with-date_time --with-chrono --with-system
3, error message:

`gcc.compile.c++ bin.v2/libs/python/build/gcc-11/release/x86_64/link-static/python-3.13/threading-multi/visibility-hidden/dict.o
In file included from ./boost/python/detail/prefix.hpp:13,
                 from ./boost/python/dict.hpp:8,
                 from libs/python/src/dict.cpp:4:
./boost/python/detail/wrap_python.hpp:57:11: fatal error: pyconfig.h: No such file or directory
   57 | # include <pyconfig.h>
      |           ^~~~~~~~~~~~
compilation terminated.

    "g++"   -fvisibility-inlines-hidden -m64 -pthread -O3 -finline-functions -Wno-inline -Wall -fvisibility=hidden  -DBOOST_ALL_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1 -DBOOST_PYTHON_SOURCE -DBOOST_PYTHON_STATIC_LIB -DNDEBUG   -I"." -I"/home/subaochen/anaconda3/envs/nogil/include/python3.13" -I"/home/subaochen/anaconda3/envs/nogil/include/python3.1t"  -c -o "bin.v2/libs/python/build/gcc-11/release/x86_64/link-static/python-3.13/threading-multi/visibility-hidden/dict.o" "libs/python/src/dict.cpp"

...failed gcc.compile.c++ bin.v2/libs/python/build/gcc-11/release/x86_64/link-static/python-3.13/threading-multi/visibility-hidden/dict.o...
gcc.compile.c++ bin.v2/libs/python/build/gcc-11/release/x86_64/link-static/python-3.13/threading-multi/visibility-hidden/str.o
In file included from ./boost/python/detail/prefix.hpp:13,
                 from ./boost/python/str.hpp:8,
                 from libs/python/src/str.cpp:4:
./boost/python/detail/wrap_python.hpp:57:11: fatal error: pyconfig.h: No such file or directory
   57 | # include <pyconfig.h>
      |           ^~~~~~~~~~~~
compilation terminated.

Obviously I missed "pyconfig.h", but i successfully compiled boost 1.86 with python 3.11 with the same step. Any suggestions? Thanks in advance!

[stefanseefeld]

@grafikrobot , do you know what's wrong here ? My b2 knowledge is next to non-existent.

[grafikrobot]

@stefanseefeld hmm.. something strange is going on with the include paths for python:

-I"/home/subaochen/anaconda3/envs/nogil/include/python3.13"
-I"/home/subaochen/anaconda3/envs/nogil/include/python3.1t"

It would help if we got the output of running the build with the --debug-configuration option.

[rgommers]

I can reproduce this build error if I leave out the include="/path/to/include/python3.13t/" part, if I add it things do work. Full reproducer:

$ git clone git@github.com:boostorg/boost.git
$ git submodule update --init --recursive
$ cd boost

$ conda create -n boostpython python-freethreading  compilers
$ conda activate boostpython
$ ./bootstrap.sh --with-python=$(which python)
$ ./b2 --toolset=gcc --with-python --with-thread --with-date_time --with-chrono --with-system
...
    "g++"   -fvisibility-inlines-hidden -m64 -pthread -O3 -finline-functions -Wno-inline -Wall -fvisibility=hidden  -DBOOST_ALL_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1 -DBOOST_CONTAINER_NO_LIB=1 -DBOOST_CONTAINER_STATIC_LINK=1 -DBOOST_PYTHON_SOURCE -DBOOST_PYTHON_STATIC_LIB -DNDEBUG   -I"." -I"/home/rgommers/code/tmp/boost/libs/any/include" -I"/home/rgommers/code/tmp/boost/libs/assert/include" -I"/home/rgommers/code/tmp/boost/libs/bind/include" -I"/home/rgommers/code/tmp/boost/libs/concept_check/include" -I"/home/rgommers/code/tmp/boost/libs/container/include" -I"/home/rgommers/code/tmp/boost/libs/container_hash/include" -I"/home/rgommers/code/tmp/boost/libs/conversion/include" -I"/home/rgommers/code/tmp/boost/libs/core/include" -I"/home/rgommers/code/tmp/boost/libs/describe/include" -I"/home/rgommers/code/tmp/boost/libs/detail/include" -I"/home/rgommers/code/tmp/boost/libs/function/include" -I"/home/rgommers/code/tmp/boost/libs/integer/include" -I"/home/rgommers/code/tmp/boost/libs/intrusive/include" -I"/home/rgommers/code/tmp/boost/libs/iterator/include" -I"/home/rgommers/code/tmp/boost/libs/lexical_cast/include" -I"/home/rgommers/code/tmp/boost/libs/move/include" -I"/home/rgommers/code/tmp/boost/libs/mp11/include" -I"/home/rgommers/code/tmp/boost/libs/mpl/include" -I"/home/rgommers/code/tmp/boost/libs/optional/include" -I"/home/rgommers/code/tmp/boost/libs/predef/include" -I"/home/rgommers/code/tmp/boost/libs/property_map/include" -I"/home/rgommers/code/tmp/boost/libs/python/include" -I"/home/rgommers/code/tmp/boost/libs/smart_ptr/include" -I"/home/rgommers/code/tmp/boost/libs/throw_exception/include" -I"/home/rgommers/code/tmp/boost/libs/tuple/include" -I"/home/rgommers/code/tmp/boost/libs/type_index/include" -I"/home/rgommers/code/tmp/boost/libs/type_traits/include" -I"/home/rgommers/code/tmp/boost/libs/utility/include" -I"/home/rgommers/mambaforge/envs/boostpython/include/python3.13" -I"libs/config/include"  -c -o "bin.v2/libs/python/build/gcc-13/release/x86_64/link-static/python-3.13/threading-multi/visibility-hidden/exec.o" "/home/rgommers/code/tmp/boost/libs/python/src/exec.cpp"

...failed gcc.compile.c++ bin.v2/libs/python/build/gcc-13/release/x86_64/link-static/python-3.13/threading-multi/visibility-hidden/exec.o...
gcc.compile.c++ bin.v2/libs/python/build/gcc-13/release/x86_64/link-static/python-3.13/threading-multi/visibility-hidden/object/function_doc_signature.o
In file included from ./boost/python/detail/prefix.hpp:13,
                 from ./boost/python/converter/registrations.hpp:8,
                 from /home/rgommers/code/tmp/boost/libs/python/src/object/function_doc_signature.cpp:9:
./boost/python/detail/wrap_python.hpp:57:11: fatal error: pyconfig.h: No such file or directory
   57 | # include <pyconfig.h>
      |           ^~~~~~~~~~~~
compilation terminated.

Change the build command to add an explicit include path:

$ ./b2 --toolset=gcc --with-python include=/home/rgommers/mambaforge/envs/boostpython/include/python3.13t --with-thread --with-date_time --with-chrono --with-system
...
The Boost C++ Libraries were successfully built!

The generated project-config.jam file does set the path to the root dir for the Python executable, but no related include path:

# B2 Configuration
# Automatically generated by bootstrap.sh

import option ;
import feature ;

# Compiler configuration. This definition will be used unless
# you already have defined some toolsets in your user-config.jam
# file.
if ! gcc in [ feature.values <toolset> ]
{
    using gcc ; 
}

project : default-build <toolset>gcc ;

# Python configuration
import python ;
if ! [ python.configured ]
{
    using python : 3.13 : "/home/rgommers/mambaforge/envs/boostpython" ;
}

path-constant ICU_PATH : /usr ;


# List of --with-<library> and --without-<library>
# options. If left empty, all libraries will be built.
# Options specified on the command line completely
# override this variable.
libraries =  ;

# These settings are equivalent to corresponding command-line
# options.
option.set prefix : /usr/local ;
option.set exec-prefix : /usr/local ;
option.set libdir : /usr/local/lib ;
option.set includedir : /usr/local/include ;

# Stop on first error
option.set keep-going : false ;

Knowing where that include path is set would be helpful I guess (I'm not familiar with b2 either) - or is it expected that one has to manually add it if the python executable isn't the system one?

It would help if we got the output of running the build with the --debug-configuration option.

Output up the the first build failure

notice: found boost-build.jam at /home/rgommers/code/tmp/boost/boost-build.jam
notice: loading B2 from /home/rgommers/code/tmp/boost/tools/build/src/build-system.jam
notice: Searching '/etc' '/home/rgommers' '/home/rgommers/code/tmp/boost/tools/build/src/util' '/home/rgommers/code/tmp/boost/tools/build/src/tools' '/home/rgommers/code/tmp/boost/tools/build/src/options' '/home/rgommers/code/tmp/boost/tools/build/src/engine' '/home/rgommers/code/tmp/boost/tools/build/src/contrib' '/home/rgommers/code/tmp/boost/tools/build/src/build' '/home/rgommers/code/tmp/boost/tools/build/src' for site-config configuration file 'site-config.jam'.
notice: Configuration file 'site-config.jam' not found in '/etc' '/home/rgommers' '/home/rgommers/code/tmp/boost/tools/build/src/util' '/home/rgommers/code/tmp/boost/tools/build/src/tools' '/home/rgommers/code/tmp/boost/tools/build/src/options' '/home/rgommers/code/tmp/boost/tools/build/src/engine' '/home/rgommers/code/tmp/boost/tools/build/src/contrib' '/home/rgommers/code/tmp/boost/tools/build/src/build' '/home/rgommers/code/tmp/boost/tools/build/src'.
notice: Searching '/home/rgommers' '/home/rgommers/code/tmp/boost/tools/build/src/util' '/home/rgommers/code/tmp/boost/tools/build/src/tools' '/home/rgommers/code/tmp/boost/tools/build/src/options' '/home/rgommers/code/tmp/boost/tools/build/src/engine' '/home/rgommers/code/tmp/boost/tools/build/src/contrib' '/home/rgommers/code/tmp/boost/tools/build/src/build' '/home/rgommers/code/tmp/boost/tools/build/src' for user-config configuration file 'user-config.jam'.
notice: Configuration file 'user-config.jam' not found in '/home/rgommers' '/home/rgommers/code/tmp/boost/tools/build/src/util' '/home/rgommers/code/tmp/boost/tools/build/src/tools' '/home/rgommers/code/tmp/boost/tools/build/src/options' '/home/rgommers/code/tmp/boost/tools/build/src/engine' '/home/rgommers/code/tmp/boost/tools/build/src/contrib' '/home/rgommers/code/tmp/boost/tools/build/src/build' '/home/rgommers/code/tmp/boost/tools/build/src'.
notice: Searching '.' for project-config configuration file 'project-config.jam'.
notice: Loading project-config configuration file 'project-config.jam' from '.'.
notice: will use 'g++' for gcc, condition <toolset>gcc-13
notice: using gcc libraries :: <toolset>gcc-13 :: /home/rgommers/mambaforge/envs/boostpython/bin /home/rgommers/mambaforge/envs/boostpython/lib /home/rgommers/mambaforge/envs/boostpython/lib32 /home/rgommers/mambaforge/envs/boostpython/lib64
notice: using gcc archiver :: <toolset>gcc-13 :: /home/rgommers/mambaforge/envs/boostpython/x86_64-conda-linux-gnu/bin/ar
warning: toolset gcc initialization: can not find tool windres
warning: initialized from project-config.jam:12
notice: using rc compiler :: <toolset>gcc-13 :: /home/rgommers/mambaforge/envs/boostpython/bin/as
notice: [python-cfg] Configuring python...
notice: [python-cfg]   user-specified version: "3.13"
notice: [python-cfg]   user-specified cmd-or-prefix: "/home/rgommers/mambaforge/envs/boostpython"
notice: [python-cfg] Checking interpreter command "/home/rgommers/mambaforge/envs/boostpython/bin/python3.13"...
notice: [python-cfg] running command '/home/rgommers/mambaforge/envs/boostpython/bin/python3.13 -c "from sys import *; print('version=%d.%d\nplatform=%s\nprefix=%s\nexec_prefix=%s\nexecutable=%s' % (version_info[0],version_info[1],platform,prefix,exec_prefix,executable))" 2>&1'
notice: [python-cfg] ...requested configuration matched!
notice: [python-cfg] Details of this Python configuration:
notice: [python-cfg]   interpreter command: "/home/rgommers/mambaforge/envs/boostpython/bin/python3.13"
notice: [python-cfg]   include path: "/home/rgommers/mambaforge/envs/boostpython/include/python3.13"
notice: [python-cfg]   library path: "/home/rgommers/mambaforge/envs/boostpython/lib/python3.13/config" "/home/rgommers/mambaforge/envs/boostpython/lib"
notice: [python-cfg] Checking for NumPy...
notice: [python-cfg] running command '/home/rgommers/mambaforge/envs/boostpython/bin/python3.13 -c "import sys; sys.stderr = sys.stdout; import numpy; print(numpy.get_include())"'
notice: [python-cfg] NumPy disabled. Reason:
notice: [python-cfg]   /home/rgommers/mambaforge/envs/boostpython/bin/python3.13 -c "import sys; sys.stderr = sys.stdout; import numpy; print(numpy.get_include())" aborted with 
notice: [python-cfg]   Traceback (most recent call last):
  File "<string>", line 1, in <module>
    import sys; sys.stderr = sys.stdout; import numpy; print(numpy.get_include())
                                         ^^^^^^^^^^^^
ModuleNotFoundError: No module named 'numpy'
notice: [cmdline-cfg] adding toolset=gcc to the build request.
Performing configuration checks

    - default address-model    : 64-bit [1]
    - default architecture     : x86 [1]

Building the Boost C++ Libraries.


    - symlinks supported       : yes
    - lockfree boost::atomic_flag : no [2]
    - compiler supports SSE2   : yes [2]
    - compiler supports SSE4.1 : yes [2]
    - cxx11_static_assert      : yes [2]
    - cxx11_hdr_ratio          : yes [2]
    - cxx11_template_aliases   : yes [2]
    - cxx11_decltype           : yes [2]
    - cxx11_char16_t           : yes [2]
    - cxx11_char32_t           : yes [2]
    - lockfree boost::atomic_flag : no [3]
    - compiler supports SSE2   : yes [3]
    - compiler supports SSE4.1 : yes [3]
    - cxx11_static_assert      : yes [3]
    - cxx11_hdr_ratio          : yes [3]
    - cxx11_template_aliases   : yes [3]
    - cxx11_decltype           : yes [3]
    - cxx11_char16_t           : yes [3]
    - cxx11_char32_t           : yes [3]

[1] gcc-13
[2] gcc-13/release/x86_64/python-3.13/threading-multi/visibility-hidden
[3] gcc-13/release/x86_64/link-static/python-3.13/threading-multi/visibility-hidden

Component configuration:

    - contract                 : not building
    - date_time                : building
    - exception                : not building
    - graph                    : not building
    - graph_parallel           : not building
    - headers                  : not building
    - log                      : not building
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    - thread                   : building
    - type_erasure             : not building
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    - uuid                     : not building
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    - type_traits              : not building
    - type_index               : not building
    - tuple                    : not building
    - tokenizer                : not building
    - timer                    : not building
    - throw_exception          : not building
    - system                   : building
    - stl_interfaces           : not building
    - stacktrace               : not building
    - spirit                   : not building
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    - smart_ptr                : not building
    - signals2                 : not building
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    - rational                 : not building
    - ratio                    : not building
    - random                   : not building
    - python                   : building
    - ptr_container            : not building
    - property_map             : not building
    - process                  : not building
    - predef                   : not building
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    - poly_collection          : not building
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    - lockfree                 : not building
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    - lexical_cast             : not building
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    - flyweight                : not building
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    - fiber                    : not building
    - endian                   : not building
    - dynamic_bitset           : not building
    - dll                      : not building
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    - describe                 : not building
    - crc                      : not building
    - coroutine2               : not building
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    - core                     : not building
    - conversion               : not building
    - context                  : not building
    - container_hash           : not building
    - container                : not building
    - config                   : not building
    - concept_check            : not building
    - compat                   : not building
    - cobalt                   : not building
    - chrono                   : building
    - charconv                 : not building
    - bind                     : not building
    - bimap                    : not building
    - beast                    : not building
    - atomic                   : not building
    - assign                   : not building
    - assert                   : not building
    - asio                     : not building
    - array                    : not building
    - any                      : not building

...patience...
...found 2320 targets...
...updating 1027 targets...
link.mklink boost/assert.hpp
link.mklink boost/ref.hpp
mklink-or-dir boost/function
mklink-or-dir boost/property_map
mklink-or-dir boost/graph
mklink-or-dir boost/detail
link.mklink boost/throw_exception.hpp
mklink-or-dir boost/exception
mklink-or-dir boost/assert
mklink-or-dir boost/algorithm
link.mklink boost/regex.hpp
link.mklink boost/function.hpp
link.mklink boost/foreach.hpp
link.mklink boost/optional.hpp
mklink-or-dir boost/property_tree
mklink-or-dir boost/container
mklink-or-dir boost/intrusive
mklink-or-dir boost/python
mklink-or-dir boost/mpl
link.mklink boost/cstdint.hpp
mklink-or-dir boost/bind
link.mklink boost/integer_traits.hpp
link.mklink boost/get_pointer.hpp
link.mklink boost/is_placeholder.hpp
link.mklink boost/detail/workaround.hpp
link.mklink boost/detail/binary_search.hpp
link.mklink boost/graph/graph_traits.hpp
link.mklink boost/graph/dll_import_export.hpp
link.mklink boost/graph/graphviz.hpp
link.mklink boost/graph/graphml.hpp
link.mklink boost/visit_each.hpp
link.mklink boost/graph/breadth_first_search.hpp
link.mklink boost/type.hpp
mklink-or-dir boost/core
link.mklink boost/limits.hpp
mklink-or-dir boost/preprocessor
link.mklink boost/static_assert.hpp
mklink-or-dir boost/type_traits
link.mklink boost/shared_ptr.hpp
link.mklink boost/noncopyable.hpp
link.mklink boost/version.hpp
link.mklink boost/detail/indirect_traits.hpp
link.mklink boost/detail/select_type.hpp
mklink-or-dir boost/smart_ptr
mklink-or-dir boost/pending
link.mklink boost/graph/graph_concepts.hpp
link.mklink boost/graph/visitors.hpp
link.mklink boost/graph/named_function_params.hpp
link.mklink boost/graph/overloading.hpp
link.mklink boost/graph/two_bit_color_map.hpp
mklink-or-dir boost/graph/detail
mklink-or-dir boost/concept
link.mklink boost/lexical_cast.hpp
link.mklink boost/any.hpp
link.mklink boost/graph/exception.hpp
mklink-or-dir boost/utility
link.mklink boost/detail/is_xxx.hpp
link.mklink boost/call_traits.hpp
mklink-or-dir boost/iterator
mklink-or-dir boost/align
link.mklink boost/detail/call_traits.hpp
link.mklink boost/utility/value_init.hpp
mklink-or-dir boost/any
link.mklink boost/type_index.hpp
mklink-or-dir boost/lexical_cast
link.mklink boost/shared_array.hpp
link.mklink boost/utility/enable_if.hpp
link.mklink boost/utility/result_of.hpp
link.mklink boost/preprocessor.hpp
mklink-or-dir boost/parameter
link.mklink boost/type_traits.hpp
link.mklink boost/graph/numeric_values.hpp
link.mklink boost/graph/buffer_concepts.hpp
link.mklink boost/concept_check.hpp
mklink-or-dir boost/tuple
link.mklink boost/graph/properties.hpp
link.mklink boost/graph/subgraph.hpp
link.mklink boost/graph/compressed_sparse_row_graph.hpp
link.mklink boost/graph/iteration_macros.hpp
link.mklink boost/pending/queue.hpp
mklink-or-dir boost/spirit
...on 100th target...
link.mklink boost/iterator_adaptors.hpp
link.mklink boost/compressed_pair.hpp
link.mklink boost/scoped_ptr.hpp
mklink-or-dir boost/move
link.mklink boost/weak_ptr.hpp
mklink-or-dir boost/thread
link.mklink boost/aligned_storage.hpp
link.mklink boost/graph/filtered_graph.hpp
link.mklink boost/detail/numeric_traits.hpp
mklink-or-dir boost/mp11
link.mklink boost/integer.hpp
mklink-or-dir boost/fusion
link.mklink boost/graph/graph_selectors.hpp
mklink-or-dir boost/functional
link.mklink boost/next_prior.hpp
link.mklink boost/graph/graph_mutability_traits.hpp
link.mklink boost/indirect_reference.hpp
link.mklink boost/current_function.hpp
mklink-or-dir boost/xpressive
mklink-or-dir boost/range
...patience...
mklink-or-dir boost/proto
link.mklink boost/intrusive_ptr.hpp
mklink-or-dir boost/numeric
link.mklink boost/checked_delete.hpp
link.mklink boost/utility.hpp
link.mklink boost/implicit_cast.hpp
link.mklink boost/detail/is_incrementable.hpp
link.mklink boost/functional/hash.hpp
link.mklink boost/integer_fwd.hpp
link.mklink boost/graph/adjacency_iterator.hpp
link.mklink boost/unordered_set.hpp
mklink-or-dir boost/system
mklink-or-dir boost/date_time
mklink-or-dir boost/chrono
mklink-or-dir boost/winapi
mklink-or-dir boost/predef
link.mklink boost/pointee.hpp
link.mklink boost/detail/interlocked.hpp
link.mklink boost/pending/property.hpp
mklink-or-dir boost/graph/property_maps
mklink-or-dir boost/typeof
link.mklink boost/atomic.hpp
link.mklink boost/detail/compressed_pair.hpp
...patience...
link.mklink boost/memory_order.hpp
mklink-or-dir boost/atomic
mklink-or-dir boost/pending/detail
link.mklink boost/predef.h
mklink-or-dir boost/ratio
link.mklink boost/operators.hpp
mklink-or-dir boost/unordered
mklink-or-dir boost/container_hash
link.mklink boost/utility/base_from_member.hpp
link.mklink boost/utility/binary.hpp
link.mklink boost/utility/identity_type.hpp
mklink-or-dir boost/numeric/conversion
link.mklink boost/utility/addressof.hpp
link.mklink boost/parameter/name.hpp
link.mklink boost/parameter/binding.hpp
mklink-or-dir boost/utility/detail
link.mklink boost/detail/lcast_precision.hpp
link.mklink boost/detail/basic_pointerbuf.hpp
mklink-or-dir boost/type_index
link.mklink boost/mem_fn.hpp
link.mklink boost/function_equal.hpp
link.mklink boost/parameter/is_argument_pack.hpp
mklink-or-dir boost/parameter/aux_
link.mklink boost/parameter/config.hpp
link.mklink boost/parameter/keyword.hpp
link.mklink boost/parameter/template_keyword.hpp
mklink-or-dir boost/describe
link.mklink boost/operators_v1.hpp
link.mklink boost/pending/detail/property.hpp
mklink-or-dir boost/optional
link.mklink boost/multi_index_container.hpp
mklink-or-dir boost/multi_index
link.mklink boost/foreach_fwd.hpp
mklink-or-dir boost/regex
link.mklink boost/scoped_array.hpp
link.mklink boost/regex_fwd.hpp
link.mklink boost/multi_index_container_fwd.hpp
link.mklink boost/none.hpp
link.mklink boost/exception/exception.hpp
link.mklink boost/exception/info.hpp
link.mklink boost/graph/reverse_graph.hpp
link.mklink boost/graph/adjacency_list.hpp
link.mklink boost/property_map/dynamic_property_map.hpp
link.mklink boost/property_map/property_map.hpp
link.mklink boost/property_map/shared_array_property_map.hpp
link.mklink boost/property_map/transform_value_property_map.hpp
...on 200th target...
link.mklink boost/concept_archetype.hpp
link.mklink boost/property_map/vector_property_map.hpp
link.mklink boost/smart_ptr.hpp
link.mklink boost/graph/named_graph.hpp
link.mklink boost/parameter/keyword_fwd.hpp
link.mklink boost/parameter/aux_/is_tagged_argument.hpp
link.mklink boost/parameter/aux_/arg_list.hpp
link.mklink boost/parameter/aux_/void.hpp
link.mklink boost/parameter/aux_/is_placeholder.hpp
link.mklink boost/parameter/aux_/result_of0.hpp
link.mklink boost/parameter/aux_/name.hpp
link.mklink boost/pending/container_traits.hpp
link.mklink boost/exception/to_string_stub.hpp
mklink-or-dir boost/exception/detail
link.mklink boost/none_t.hpp
mklink-or-dir boost/parameter/aux_/preprocessor
link.mklink boost/exception/to_string.hpp
link.mklink boost/unordered_map.hpp
link.mklink boost/parameter/value_type.hpp
link.mklink boost/parameter/aux_/lambda_tag.hpp
link.mklink boost/parameter/aux_/use_default_tag.hpp
link.mklink boost/parameter/aux_/yesno.hpp
link.mklink boost/parameter/aux_/is_maybe.hpp
link.mklink boost/parameter/aux_/tagged_argument_fwd.hpp
link.mklink boost/parameter/aux_/parameter_requirements.hpp
link.mklink boost/parameter/aux_/augment_predicate.hpp
link.mklink boost/parameter/aux_/template_keyword.hpp
link.mklink boost/parameter/aux_/tag.hpp
link.mklink boost/parameter/aux_/default.hpp
link.mklink boost/cast.hpp
...patience...
link.mklink boost/polymorphic_cast.hpp
link.mklink boost/parameter/aux_/unwrap_cv_reference.hpp
link.mklink boost/parameter/aux_/tagged_argument.hpp
link.mklink boost/parameter/aux_/has_nested_template_fn.hpp
mklink-or-dir boost/parameter/aux_/pack
mklink-or-dir boost/io
link.mklink boost/enable_shared_from_this.hpp
link.mklink boost/make_shared.hpp
link.mklink boost/exception_ptr.hpp
link.mklink boost/exception/diagnostic_information.hpp
common.copy /home/rgommers/code/tmp/boost/stage/lib/cmake/BoostDetectToolset-1.89.0.cmake
common.copy /home/rgommers/code/tmp/boost/stage/lib/cmake/Boost-1.89.0/BoostConfig.cmake
link.mklink boost/exception/get_error_info.hpp
link.mklink boost/exception/current_exception_cast.hpp
link.mklink boost/io_fwd.hpp
...on 300th target...
common.copy /home/rgommers/code/tmp/boost/stage/lib/cmake/Boost-1.89.0/BoostConfigVersion.cmake
common.copy /home/rgommers/code/tmp/boost/stage/lib/cmake/boost_headers-1.89.0/boost_headers-config-version.cmake
common.copy /home/rgommers/code/tmp/boost/stage/lib/cmake/boost_headers-1.89.0/boost_headers-config.cmake
common.copy /home/rgommers/code/tmp/boost/stage/lib/cmake/boost_numpy-1.89.0/boost_numpy-config-version.cmake
common.copy /home/rgommers/code/tmp/boost/stage/lib/cmake/boost_numpy-1.89.0/boost_numpy-config.cmake
gcc.compile.c++ bin.v2/libs/python/build/gcc-13/release/x86_64/python-3.13/threading-multi/visibility-hidden/list.o
In file included from ./boost/python/detail/prefix.hpp:13,
                 from ./boost/python/list.hpp:8,
                 from /home/rgommers/code/tmp/boost/libs/python/src/list.cpp:5:
./boost/python/detail/wrap_python.hpp:57:11: fatal error: pyconfig.h: No such file or directory
   57 | # include <pyconfig.h>
      |           ^~~~~~~~~~~~
compilation terminated.

I checked that my CMake is recent enough; it's at 3.31.6 while 3.30.0 is the minimum version needed for free-threaded CPython support (such versions are tracked here, I'll add Boost.Python to that table as well).

In the end this looks like all it needs is appending a single t to the include path that the build system calculates based on the Python minor version.

[rgommers]

Okay, found it I think:

https://github.com/bfgroup/b2/blob/f518c83dbbcce621df81ab29e7b2a33498a35ca2/src/tools/python.jam#L563

version is still 3.13 for a free-threaded interpreter, so what is needed is to detect that a free-threaded interpreter is being run and if so, append t. The solution will be similar to mesonbuild/meson#13338 I think: run the interpreter, and check for this sysconfig variable:

>>> import sysconfig
>>> sysconfig.get_config_var('Py_GIL_DISABLED')
1