Re: BOOST_NO_CXX11_HDR_CHRONO?

From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2020-05-15 14:40:07

On 2020-05-15 16:40, Frédéric via Boost wrote:
> Hi,
> 
> When I compile the following program:
> #include <boost/math/constants/constants.hpp>
> #include <chrono>
> int main() {
>    return 0;
> }
> with a osx cross compiler based on clang 9 on linux,I get the
> following warnings (full output below):
> CAUTION: This message was generated due to the define:
> BOOST_NO_CXX11_HDR_CHRONO [-W#pragma-messages]
> 
> This is quite strange as the compiler generates the binary which means
> there was no issue to find <chrono>.
> 
> What's wrong then?

That the header exists doesn't mean it's (reasonably) usable. 
Boost.Config has a test for <chrono>[1]. If it passes, it may be a 
reason to stop defining BOOST_NO_CXX11_HDR_CHRONO on that compiler.

[1]: 
https://github.com/boostorg/config/blob/develop/test/boost_no_cxx11_hdr_chrono.ipp