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boostorg / histogram

Fast multi-dimensional generalized histogram with convenient interface for C++14
Boost Software License 1.0
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Problem compiling with clang-9 and libc++ and c++17 #270

Closed JonasToth closed 4 years ago

JonasToth commented 4 years ago

Hi,

I am using this great library in a project that compiles with C++17 but up to date toolchains.

I believe the condition at https://github.com/boostorg/histogram/blob/a872c6e1c32e3c6000317b07aec7e416c8939c75/include/boost/histogram/detail/span.hpp#L11 is not fully correct, because e.g. clang-9 fullfills all those conditions, and has the include for <span>, but libc++ does not enable this include for C++17.

Adding a __cpp_lib_span >= 201902 as condition does fix this issue. (see https://en.cppreference.com/w/User:D41D8CD98F/feature_testing_macros#C.2B.2B20)

Thanks again for the great library!

Best Regards, Jonas

HDembinski commented 4 years ago

Thank you very much for reporting this. I also found similar issues with this, the condition is difficult to get right. If you could make a PR I would be very happy to merge it.

JonasToth commented 4 years ago

This is fixed, so closing the issue.