Re: [boost] [cmake] Pull request announcement

Subject: Re: [boost] [cmake] Pull request announcement
From: Raffi Enficiaud (raffi.enficiaud_at_[hidden])
Date: 2018-09-19 18:31:40

On 19.09.18 15:08, James E. King III via Boost wrote:
> On Mon, Sep 17, 2018 at 12:02 PM Peter Dimov via Boost <
> boost_at_[hidden]> wrote:
> 
>> Mike Dev wrote:
>>>> I'd like to see an example of how a CMake project using Boost (f.ex.
>>>> System) would look like, assuming your proposed pull requests are
>>>> accepted.
>>>
>>> Sure. You can have a look at
>> https://github.com/Mike-Devel/DummyBoostUsage
>>
>> Thanks.
>>
>>> file(GLOB boost_lib_cmake_files libs/*/CMakeLists.txt)
>>
>> I wonder what would happen if Hana, Yap or Beast are present. :-)
>>
>>
> Absolutely, positively do NOT use GLOB for project build chains or for
> header or source discovery.
> There are well documented reasons not to do this.  You must express the
> dependency chain in
> linear order in libs/CMakeLists.txt.
> 
> I would have the boostorg/CMakeLists.txt call:
> 
> add_subdirectories ( libs )
> after it has included all the things libs depends on.
> 
> Then have libs/CMakeLists.txt call add_subdirectories in dependency order.
> That is the only way you can reasonably ensure a linear dependency chain.

Maintaining the topological order at $boost/libs level is difficult and 
error prone.

I've a solution that works well for this. Please have a look there, all 
is explained:

https://github.com/raffienficiaud/boost-cmake

In particular, I use additional files like this one:
https://github.com/raffienficiaud/boost-cmake/blob/master/boost/libs/test/build/boost-decl.cmake

that for instance indicate that the "doc" component of "test" requires 
the "build" of quickbook. After that, everything gets included in the 
right order.

Raffi