Re: [boost] Re: Build Success on Boost.Python

From: Ullrich Koethe (u.koethe_at_[hidden])
Date: 2001-07-18 12:08:03

David Turner wrote:
> 
> Hello all,
> 
> David Abrahams a écrit :
> >
> > Ulli,
> >
> > the problem with this approach is that the Jam architecture does not allow
> > the running of shell commands at any point where this information can be
> > used. The info would have to be located in an environment variable at the
> > time Jam is invoked in order to be interpreted by any of the Jam code.
> >
> > I have often wished for some way to call into the system during the rule
> > evaluation phase, so I could find out things like "which version of Python
> > is installed", etc., but this would be a fairly significant change to the
> > Jam architecture and would certainly invite abuse. Maybe the best thing
> > would be to invoke Jam from a script that does a few of these jobs and
> > passes the results in variables on the Jam command-line. On the other hand,
> > there's something to be said for being able to do the whole job with a
> > single tool. I wonder what David Turner thinks of this?
> >
> The solution would be to implement a new built-in (let's name it "EXEC" or "SHELL")
> that would return the output of a shell command like in:
> 
>    uname = [ EXEC "uname -a" ] ;
> 
> the built-in SUBST could also be used to filter the fields then :o)
> 

This looks good. It would be even better if the command's return/exit
code could also be retrieved within Jam :-)

> The problem is that we need to redirect the standard output to a Jam
> string (if it's small enough). GNU Make already provides something similar
> with its "shell" function, but the Win32 implementation is definitely
> _not_ pretty.
> 

I've had a look at the Python implementation of this functionality, and
it's also not exactly a straightforward solution. But at least it's
clean and comprehensible code.

Perhaps, for the particular task of finding out the OS name and version,
I direct library call would be easier? 

Regards
Ulli
-- 
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| Ullrich Koethe  Universität Hamburg / University of Hamburg    |
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