Re: [boost] find_package(Boost) support

Subject: Re: [boost] find_package(Boost) support
From: Peter Dimov (lists_at_[hidden])
Date: 2019-02-01 14:13:01

Roger Leigh wrote:
> A heads up from the CMake side.  Unfortunately, this is causing breakage 
> with FindBoost, and we got the first bug:
>
>    https://gitlab.kitware.com/cmake/cmake/issues/18865

The complaint about not setting Boost_LIBRARIES is correct, and I don't 
think we should be setting it in 2019. I understand that FindBoost can't 
remove it for compatibility reasons, but new code should not be propagating 
"old CMake" practices.

Regarding static/shared, the config files link to whatever is specified with 
Boost_USE_STATIC_LIBS (ON/OFF); when not set, they link to shared when 
BUILD_SHARED_LIBS is ON, to static otherwise.

The alternative behavior under consideration was to always prefer shared 
unless Boost_USE_STATIC_LIBS=ON. Some people prefer the one, some the other, 
and I have no real way to gauge which one is better or more useful, with so 
little feedback.

The FindBoost behavior - link to whatever's found - is not easy to duplicate 
under our scheme and I won't be pursuing it.

> It looks like for the specific modules concerned, it's not behaving 
> entirely compatibly with FindBoost.  Would it be possible to rectify this?

I don't think that we can achieve exact compatibility even if we wanted to.