Re: [avr-gcc-list] Makefiles, $(AS) $(ASFLAGS) - simple-minded question

[Dave N6NZ]

Anton Erasmus wrote:
> On 23 Feb 2008 at 23:12, Dave N6NZ wrote:
>
> > Anton Erasmus wrote:
> > > Normally .S (Upper case S) should be processed by avr-gcc and not by avr-as. 
> > > .S files are first pre-processed by the normal C processor.
> > I see that now from some other documentation that I found.
> >
> > > avr-gcc have no concept of $(ASFLAGS) or any other make definition.
> > Not quite true... there is a list of environment variables that the gcc 
> > driver consults.  It turns out ASFLAGS is not one of them, even if it 
> > does get exported, which is the root of my question.
>
> Make variables are not environment variables. One can define variables in the
> environment, which then can be used by make, but variables defined in make
> are not necessarily visible in the environment from which the make file was 
> executed.
> Also make variable are evaluated only when needed, not when first found in the make file. 
> Also the same variable in a make file can have a different value depending on when it is 
> used.

YES YES YES OF COURSE!!!! AND I AM SHOUTING!!!!

I understand all these trivial basics. I first wrote a makefile over 30 
years ago. The points is, they *can* be exported, and since I am writing 
makefiles that are called from other makefiles, I have exported 
variables to communicate between them.  As it turns out, I decided not 
to export ASMFLAGS for other reasons.  And I found the definitive 
documentation needed to avoid collisions.

I was only asking the *very* simple question of how to determine if I 
would collide with the gcc driver.  Which is well documented, once I 
found the right place to look.  You do realize gcc is not a monolithic 
executable?

*grump*

-dave

> O'Reilly publishes a very nice book "Managing projects with gnu make". This is an excellent 
> book which explains the sometime odd behaviour of make variables very well.
>
> Regards
>   Anton Erasmus-- 
> A J Erasmus
>
>
>
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