unknown type name 'BOOST_CONSTEXPR'

[NAThompson]

Just ran the examples:

➜  example git:(develop) ✗ ../../../b2 --reconfigure cxxflags="--std=c++17 -Wfatal-errors"
Performing configuration checks

    - default address-model    : 64-bit
    - default architecture     : x86
    - symlinks supported       : yes
    - BOOST_COMP_GNUC >= 4.3.0 : no
    - Boost.Config Feature Check: cxx11_hdr_tuple : yes
    - Boost.Config Feature Check: cxx11_auto_declarations : yes
    - Boost.Config Feature Check: cxx11_defaulted_functions : yes
    - Boost.Config Feature Check: cxx11_lambdas : yes
    - Boost.Config Feature Check: cxx11_numeric_limits : yes
    - GCC libquadmath and __float128 support : no
    - Boost.Config Feature Check: cxx11_explicit_conversion_operators : yes
    - Boost.Config Feature Check: cxx11_smart_ptr : yes
    - Boost.Config Feature Check: cxx11_function_template_default_args : yes
    - Boost.Config Feature Check: cxx11_unified_initialization_syntax : yes
    - Boost.Config Feature Check: cxx11_allocator : yes
    - Boost.Config Feature Check: cxx11_hdr_random : yes
    - Boost.Config Feature Check: cxx11_hdr_thread : yes
    - Boost.Config Feature Check: cxx11_hdr_atomic : yes
    - Boost.Config Feature Check: cxx11_decltype : yes
    - Boost.Config Feature Check: cxx11_hdr_future : yes
    - Boost.Config Feature Check: cxx11_hdr_chrono : yes
    - Boost.Config Feature Check: cxx17_if_constexpr : yes
    - Boost.Config Feature Check: cxx17_std_apply : yes
    - Boost.Config Feature Check: cxx11_inline_namespaces : yes
darwin.compile.c++ ../../../bin.v2/libs/math/example/catmull_rom_example.test/darwin-4.2.1/debug/threading-multi/visibility-hidden/catmull_rom_example.o
In file included from catmull_rom_example.cpp:11:
../../../boost/math/interpolators/catmull_rom.hpp:23:11: fatal error: unknown type name 'BOOST_CONSTEXPR'
   inline BOOST_CONSTEXPR std::size_t size(const C& c)
          ^
1 error generated.

    "g++"   -fvisibility-inlines-hidden -fPIC -m64 -O0 -fno-inline -Wall -g -fvisibility=hidden -dynamic -gdwarf-2 -fexceptions --std=c++17 -Wfatal-errors -Wno-missing-braces -DBOOST_ALL_NO_LIB=1  -I"../../.." -I"../include_private" -c -o "../../../bin.v2/libs/math/example/catmull_rom_example.test/darwin-4.2.1/debug/threading-multi/visibility-hidden/catmull_rom_example.o" "catmull_rom_example.cpp"

Strangely, I don't understand why this is popping up here. I went and checked out develop on boost.config, but no joy.

Is BOOST_CONSTEXPR semantic sugar in this case? Can it be removed without fear?

[pabristow]

From: Nick notifications@github.com Sent: 5 July 2019 23:42 To: boostorg/math math@noreply.github.com Cc: Subscribed subscribed@noreply.github.com Subject: [boostorg/math] unknown type name 'BOOST_CONSTEXPR' (#226)

Just ran the examples:

➜ example git:(develop) ✗ ../../../b2 --reconfigure cxxflags="--std=c++17 -Wfatal-errors"

Performing configuration checks

- default address-model    : 64-bit

- default architecture     : x86

- symlinks supported       : yes

- BOOST_COMP_GNUC >= 4.3.0 : no

- Boost.Config Feature Check: cxx11_hdr_tuple : yes

- Boost.Config Feature Check: cxx11_auto_declarations : yes

- Boost.Config Feature Check: cxx11_defaulted_functions : yes

- Boost.Config Feature Check: cxx11_lambdas : yes

- Boost.Config Feature Check: cxx11_numeric_limits : yes

- GCC libquadmath and __float128 support : no

- Boost.Config Feature Check: cxx11_explicit_conversion_operators : yes

- Boost.Config Feature Check: cxx11_smart_ptr : yes

- Boost.Config Feature Check: cxx11_function_template_default_args : yes

- Boost.Config Feature Check: cxx11_unified_initialization_syntax : yes

- Boost.Config Feature Check: cxx11_allocator : yes

- Boost.Config Feature Check: cxx11_hdr_random : yes

- Boost.Config Feature Check: cxx11_hdr_thread : yes

- Boost.Config Feature Check: cxx11_hdr_atomic : yes

- Boost.Config Feature Check: cxx11_decltype : yes

- Boost.Config Feature Check: cxx11_hdr_future : yes

- Boost.Config Feature Check: cxx11_hdr_chrono : yes

- Boost.Config Feature Check: cxx17_if_constexpr : yes

- Boost.Config Feature Check: cxx17_std_apply : yes

- Boost.Config Feature Check: cxx11_inline_namespaces : yes

darwin.compile.c++ ../../../bin.v2/libs/math/example/catmull_rom_example.test/darwin-4.2.1/debug/threading-multi/visibility-hidden/catmull_rom_example.o

In file included from catmull_rom_example.cpp:11:

../../../boost/math/interpolators/catmull_rom.hpp:23:11: fatal error: unknown type name 'BOOST_CONSTEXPR'

inline BOOST_CONSTEXPR std::size_t size(const C& c)

      ^

1 error generated.

"g++"   -fvisibility-inlines-hidden -fPIC -m64 -O0 -fno-inline -Wall -g -fvisibility=hidden -dynamic -gdwarf-2 -fexceptions --std=c++17 -Wfatal-errors -Wno-missing-braces -DBOOST_ALL_NO_LIB=1  -I"../../.." -I"../include_private" -c -o "../../../bin.v2/libs/math/example/catmull_rom_example.test/darwin-4.2.1/debug/threading-multi/visibility-hidden/catmull_rom_example.o" "catmull_rom_example.cpp"

Strangely, I don't understand why this is popping up here. I went and checked out develop on boost.config, but no joy.

Is BOOST_CONSTEXPR semantic sugar in this case? Can it be removed without fear?

This suggest s to me that BOOST_CONSTEXPR isn’t defined for Darwin platform, so

I think that you could try BOOST_CONST_OR_CONSTEXPR here instead.

https://www.boost.org/doc/libs/1_70_0/libs/config/doc/html/boost_config/boost_macro_reference.html Some compilers don't support the use of constexpr. This macro expands to const on those compilers, and constexpr elsewhere. For example, when defining const expr variables replace: static constexpr UIntType xor_mask = a; with: static BOOST_CONSTEXPR_OR_CONST UIntType xor_mask = a;

HTH

Paul

[jzmaddock]

No there was a missing #include, fixed in the commit referenced above.

[jzmaddock]

Well that turned into a CI bloodbath, still the newly added concept checks (which were there all along, they just weren't activated in the Jamfile), did trap a number of issues. Just pushed another fix for those and cancelled the Appveyor build.