Re: [Boost-build] What is _message_

Subject: Re: [Boost-build] What is _message_
From: Edward Diener (eldiener_at_[hidden])
Date: 2016-06-03 12:06:47

On 6/3/2016 9:55 AM, Rene Rivera wrote:
> On Fri, Jun 3, 2016 at 8:41 AM, Edward Diener <eldiener_at_[hidden]
> <mailto:eldiener_at_[hidden]>> wrote:
>
>     On 6/3/2016 9:18 AM, Rene Rivera wrote:
>
>         On Fri, Jun 3, 2016 at 7:17 AM, Edward Diener
>         <eldiener_at_[hidden] <mailto:eldiener_at_[hidden]>
>         <mailto:eldiener_at_[hidden]
>         <mailto:eldiener_at_[hidden]>>> wrote:
>
>             I am seeing in the predef.jam file a call to rule _message_
>         but I
>             can find no information on it. Does this exist in some Boost
>         Build
>             jam file ?
>
>
>         That's not a rule.. It's a variable. Or rather, a group of
>         variables.
>
>
>     How does the syntax:
>
>     _message_(/check/predef//predef_check_cc_$(key))
>
>     apply to a Boost Build variable ? I thought Boost Build variables (
>     which are list of strings ) had to use [n] to access a string in the
>     list.
>
>
> That's, literally, the name of the variable. Variables in bjam have
> almost no limitations on characters allowed. In this case, because it
> has a variable expansion in it, the name comes out to be something like:
>
>   _message_(/check/predef//predef_check_cc_79054025255fb1a26e4bc422aef54eb4)
>
> I.e. it's a variable that is specifically named for the target of a
> specific predef check sub/expression. If you where indexing an element
> in the variable's list value you would then end up with:
>
>
> _message_(/check/predef//predef_check_cc_79054025255fb1a26e4bc422aef54eb4)[0]
>
> For example.

Thanks and understood !