Re: [Boost-build] Boost-build Digest, Vol 69, Issue 8

Subject: Re: [Boost-build] Boost-build Digest, Vol 69, Issue 8
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2011-05-13 10:49:49

AMDG

On 05/13/2011 07:35 AM, Michael Krajnak wrote:
> Great!  That works, what I have is:
> 
>     import toolset ;
>     import os ;
>     local stlDir = [ os.environ "STLPORT" ] ;
>     ...
>     using stlport : 5.2.1 :
>     $(stlDir)/stlport :
>     $(stlDir)/lib/evc9-x86 ;
> 
> I do have a question about the "?=" syntax in your example.
> 
>     programFiles ?= [ os.envron "ProgramFiles" ] ;
> 
> I assume this is "set value if not already set", something like "if
> !programFiles then programFiles = ..."
> 

Exactly.

> I wanted to a hard code a default value so I put something like:
> 
>     stlDir ?= [ "default/path/to/stlport"] ;
> 
> But I get the following message:
> 
>     user-config.jam:43: in modules.load rule D:/dev/sapphire/stlport
> unknown in module user-config.
> 
> I can live without this, but at this point I would like to understand
> what's happening here.
> 

Leave out the brackets.  They're used to call a function.

stlDir ?= "default/path/to/stlport" ;

In Christ,
Steven Watanabe