On Thu, Jul 23, 2015 at 09:08:15PM +0200, Jakub Wilk wrote: > * Eduard Bloch <e...@gmx.de>, 2015-07-23, 19:43: > >The problem: I see lots of $(shell ...) stuff. In boost, there are about > >12 such calls. And they run dpkg-architecture or dpkg-parsechangelogs or > >similar commands. When this was done a just couple of times (i.e. before > >dh(7)), that's acceptable. But now, it looks like debian/rules is called > >many, many times through dh. > > One mistake boost makes is using ":=" instead of plain "=". Contrary to > popular belief, the former almost always causes more evaluation of $(shell) > stuff, specially when dh is involved.
Or you can use: lazy = $(eval $(1) = $$(if $$(___$(1)),,$$(eval ___$(1) := $(2)))$$(___$(1))) $(call lazy,VARIABLE_NAME,$$(shell command)) And then the command will only execute when you actually use VARIABLE_NAME for the first time. Mike -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
