Re: [boost] [build] Default compiler options for a toolset

Subject: Re: [boost] [build] Default compiler options for a toolset
From: Gavin Lambert (gavinl_at_[hidden])
Date: 2013-11-18 23:08:56

On 19/11/2013 16:48, Quoth Edward Diener:
> There are 4 lines of C++FLAGS
>
>      toolset.flags msvc.compile C++FLAGS
> <exception-handling>on/<asynch-exceptions>off/<extern-c-nothrow>off :
> /EHs ;
>      toolset.flags msvc.compile C++FLAGS
> <exception-handling>on/<asynch-exceptions>off/<extern-c-nothrow>on :
> /EHsc ;
>      toolset.flags msvc.compile C++FLAGS
> <exception-handling>on/<asynch-exceptions>on/<extern-c-nothrow>off : /EHa ;
>      toolset.flags msvc.compile C++FLAGS
> <exception-handling>on/<asynch-exceptions>on/<extern-c-nothrow>on : /EHac ;
>
> How is a particular one chosen ?

I've never really looked into it, but it's pretty clear from the above 
that it will select whichever line matches the AND-combination of the 
settings on that line.  So eg. you'll get /EHs if exception-handling=on 
and asynch-exceptions=off and extern-c-nothrow=off.

As for those settings, they'll either be defined in project-config.jam 
or one of the library, compiler, or builtin jam files.  (Presumably 
searched in that order.)  But that's just a guess.