boost-1.68.0: error: ignoring #pragma detect_mismatch about config

[jzmaddock]

boost/config/user.hpp is for user-specific defines, ie stuff that we don't set. In particular we do not set BOOST_HAS_PRAGMA_DETECT_MISMATCH for gcc as it's unsupported by that compiler. Has someone edited your user.hpp?

[0-wiz-0]

No, the file is still like it was installed using pkgsrc.
The pkgsrc patches for boost are available here:
http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/meta-pkgs/boost/patches/?only_with_tag=MAIN

What do you mean with "we don't set it" - how is the file generated? Where can I look for the code that might add this symbol?

[jzmaddock]

OK found it - they're running the configure script and taking the results as correct even though it's really only a first guess - there are some things that are quite hard to test for. Let me double check the script.

[jzmaddock]

Here's what's happening: when the configure script is run, then -Werror=unknown-pragmas is not set and the test case compiles (albeit with a warning) so the script thinks that the pragma is supported. Then when you compile your code with -Werror or whatever then it crashes and burns.

I could manually tweak the test case so it fails for any unsupported compilers, but that sort of defeats the object really. For now I suggest you just comment out the line the config/user.hpp that defines BOOST_HAS_PRAGMA_DETECT_MISMATCH

BTW the configure script does print out right at the start:

Note that this test script only gives an approximate
configuration - you will need to test the results carefully
using the boost regression test suite before using the results.

It was really designed to give a first approximation when porting Boost to a new platform, usually relying on the pre-configured headers will give better results.

[0-wiz-0]

I changed pkgsrc to use the pre-generated user.hpp file instead.
Thank you for your helpful advice!