On 29 January, 2015 - Thiago Macieira wrote:
> On Wednesday 28 January 2015 11:04:21 Linus Torvalds wrote:
> > The proper way to get the git version is to just do
> >
> > # get raw SHA1
> > git rev-parse HEAD
> >
> > # get "description" of it
> > git describe --tags --abbrev=12
> >
> > but actually accessing the .git/HEAD file directly is very wrong. But
> > I have no idea how to do git commands in the *.pri file, and handling
> > failure gracefully (in case it's not a git repository etc).
>
> You're right, but this implies always running the rule. That implies Make
> must
> find that a given file is not up to date, otherwise it won't run the rule. In
> turn, it means the not-up-to--date status cascades down to the binary and
> Make
> will recompile and relink, even if nothing changed.
>
> I don't know of a way to ask Make to always run some commands and inspect
> file
> contents before deciding what is up to date and what isn't. The closest I can
> think of is to touch or not touch another file, but in a parallel build Make
> may have already inspected that file and decided it was up-to-date.
>
> Do you know of any tricks I'm missing?
I've successfully managed to fool make into doing the right thing by
conditionally declaring a target as .PHONY, but i guess that trick could
be used on a dependency.
.PHONY: $(shell for f in $(DATA) $(GEN) ; do \
if [ -e $$f ] && [ $$(( $$(date +%s) - $$(date -r $$f +%s))) -gt
$$(($(MAX_AGE)*60)) ] ; then \
echo $$f ; \
fi \
done)
Such a trick might be plausible to use to conditionally declaring that
dependency or not.
//Anton
--
Anton Lundin +46702-161604
_______________________________________________
subsurface mailing list
subsurface@subsurface-divelog.org
http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
