Re: [Boost-build] How to remove specific compiler/linker flags

Subject: Re: [Boost-build] How to remove specific compiler/linker flags
From: Anthony Foglia (AFoglia_at_[hidden])
Date: 2010-05-06 13:53:24

Boris Schaeling wrote:
> On Thu, 06 May 2010 16:36:11 +0200, Anthony Foglia 
> <AFoglia_at_[hidden]> wrote:
> 
>> Boris Schaeling wrote:
>>> On Thu, 06 May 2010 08:28:57 +0200, Benjamin Prestele 
>>> <benjamin.prestele_at_[hidden]> wrote:
>>>
>>>> [...]while the <optimization>off gets propagated down to all 
>>>> dependent targets, the <cxxflags> do not. So basically all dependent 
>>>> targets need to to be updated with the additional <cxxflags>.
>>>  If the dependent targets are all defined in Jamfiles I think you can 
>>> use:
>>>  project : requirements <cxxflags>-O2 ;
>>
>> What if he made a new variant?  Would that get propagated?  Or would a 
>> feature?  (What if the feature were link-incompatible?)
> 
> While you can create a new propagating feature (have a look at 
> /tools/build/v2/tools/builtin.jam where features are defined) the 
> feature would need to be used somewhere. But I'm out now as I never made 
> myself familiar with the script language bjam is based on (I'm waiting 
> for the Python port :).

You can set the feature from the command-line.  So if he did something like

feature.feature optimize-no-dead-strip : on off : composite propagated ;
feature.compose <optimize-no-dead-strip>
   : on
   : <cflags>-O2
   ;
feature.compose <optimize-no-dead-strip>
   : off
   : # You might need something here, but I don't know what's appropriate
   ;

Then set <optimize-no-dead-strip>on as a requirement of the the top-most 
project (or set it to , it will be propagated down to all dependent 
projects.  Or you could set it from the command line with
bjam optimize-no-dead-strip=on

The other option is to define a optimize-darwin variant and use that.

-- 
Anthony Foglia
Princeton Consultants
[phone] x233