On Tue, Jan 28, 2014 at 1:20 PM, Paul Smith <psm...@gnu.org> wrote:
> I'm not sure I'd go that far. $(shell ...) really _is_ useless in a
> recipe because make will invoke a shell to run the recipe anyway, so why
> have it invoke two shells? It's just redundant.
>
> However, $(file ...) can be useful in a recipe especially on systems
> which have limited command line lengths (Windows for example)... in fact
> I'd say that this is one of the main reasons people wanted $(file ...).
I'll grant you your point about $(file ...); sorry for overstating.
But (and here we go completely away from the original topic, sorry
again) I think $(shell ...) in a recipe should be more firmly
deprecated than you do here. It's not just redundant, it creates an
order-of-evaluation error. See the third date in this example:
% cat Makefile
all:
@echo The time is now $$(date)
@echo The time is now $(shell date)
sleep 4
@echo The time is now $(shell date)
@echo The time is now $$(date)
% make
The time is now Tue Jan 28 13:31:08 EST 2014
The time is now Tue Jan 28 13:31:08 EST 2014
sleep 4
The time is now Tue Jan 28 13:31:08 EST 2014
The time is now Tue Jan 28 13:31:12 EST 2014
David
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