Re: [Boost-build] [build] Compiler requirement for a header only library

Subject: Re: [Boost-build] [build] Compiler requirement for a header only library
From: Matthew Chambers (matt.chambers42_at_[hidden])
Date: 2011-04-26 18:40:52

On 4/26/2011 7:03 AM, Vladimir Prus wrote:
> On Tuesday, April 26, 2011 05:58:47 Dean Michael Berris wrote:
>> On Tue, Apr 26, 2011 at 8:25 AM, Edward Diener<eldiener_at_[hidden]>  wrote:
>>> I have a header only library, which needs a particular compiler
>>> requirement to be set when the library's header files are included. I do
>>> not want to have to change the jam file for every library which uses my
>>> library. Is there a way to do this with Boost Build so that any library
>>> which includes one of my library's header files has the particular
>>> option for the particular compiler set properly. I do know about
>>> conditional requirements in Boost Build but I do not understand how a
>>> particular jamfile in a header directory can enforce such an option for
>>> other libraries.
>>
>> In your header-only lib you can check for the options used to compile
>> it -- if it's not there, use #error or #warning to let the user know
>> what's to be done.
>>
>> I'm not sure if there's a way to do this in Boost.Build itself,
>> although it would be awesome if there was a way to do this.
>
> While Boost.Build can technically do this, there are two problems:
>
> - Each Boost library would have to explicitly list other Boost
> header-only libraries that it uses
> - Use code, which might not be using Boost.Build, won't take advantage
> of this.
>
> I don't know how to overcome those issues.
>

Pretty much by definition you can't enforce compiler parameters with a build system when the object 
of the enforcement doesn't ever need to be built! A header-only library never needs to be mentioned 
in a Jamfile (i.e. even if user code DOES use Boost.Build it likely won't be specifying it in Jamfiles).

-Matt