Re: [Boost-build] Help using $(JAMDATE)

From: Vladimir Prus (ghost_at_[hidden])
Date: 2008-03-17 01:57:56

Miguel Ramos wrote:

> Hello,
> 
> I'm having trouble using the JAMDATE built-in variable. I'm using
> Boost.Build for a few months now, and need to replace uses of the
> output of the UNIX date command with something which is platform
> independent.
> 
> The problem is I can't get JAMDATE however I use it. Apparently, it is
> expanded to an empty variable.
> The most basic use of it is something like
> <define>BUILD_DATE=\\\"$(JAMDATE)\\\" and what happens is that the
> -DBUILD_DATE=something compiler argument is being omited. If I replace
> that with some other variable which has content, then the argument is
> emited.
> 
> I tried using JAMDATE in a constant in Jamroot and bjam tells me that
> the variable is empty.
> I looked into the source file src/jam.c to check if the variable
> definition was inside some conditional compilation directive (maybe my
> bjam on Gentoo Linux is being incorrectly built) but it looks like it
> isn't.
> 
> What am I doing wrong? How can I have that preprocessor macro defined?

The JAMDATE is a builtin Jam variable and is defined in the global
module. Use

        import modules ;
        JAMDATE = [ modules.peek : JAMDATE ] ;

to get that variable in a Jamfile.

HTH,
Volodya