Re: [jamboost] Finding out where output files are and changing it + precompiled headers

From: Vladimir Prus (ghost_at_[hidden])
Date: 2005-07-06 10:04:35

Hi Andrey,
Hi Jim,

> > 2. In my compiler flags <cflag> I'd like to reference the output
> > directory (the one we changed in 1). This is for this specific instance
> > for precompiled headers, so the actual flag I want to pass is something
> > like this (but of course I don't know the proper variablenames):
> >
> > <cflag>-Fp$(intermediate_path)/$(project_name).pch
>
> It isn't a good idea to specify cflags manually in jamfile. It's better
> to patch msvc.jam toolset definition file and create features like
>
> <pch>off|use|create|hdrstop
> <pch-header>StdAfx.h
> <pch-db>StdAfx.pch
>
> Also you need to track dependencies correctly: all files with <pch>use
> should depend on StdAfx.pch, and stdafx.cpp should create StdAfx.pch
> output.
>
> Can someone more fluent in bbv2 tell me is this a lot of work?

This PCH thing becomes a common request. Recall that msvc has both "automatic" 
pch mode, that requires, IIRC, a single switch, and "manual" mode, that 
requires creating PCH once, and then using it from other targets. I recall 
I've suggested the following syntax for the manual mode:

pch stl : stl.h :
exe my : my.cpp : <pch>stl ;

I think this should not be too hard to add. 

> Also I wonder how other compilers besides msvc implement precompiler
> headers? 

borland, como, gcc

> It looks like bcb can use #pragma hdrstop too. 

And, BTW, I forgot that #pragma hdrstop does ;-) Gcc does not have it, IIRC.

- Volodya

-- 
Vladimir Prus
http://vladimir_prus.blogspot.com
Boost.Build V2: http://boost.org/boost-build2