From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2008-08-12 15:46:24
Ray Lambert wrote:
>> As for 'files modified by external conditions', I believe Boost Build
>> assumes it knows about all dependencies between targets. To give it that
>> have you tries modeling your tools using Boost Build target or generator?
> I've tried a few things like this but I haven't successfully gotten it to
> work. It may just be due to me not understanding the internals enough to
> "press the right buttons" (so to speak).
> I need to run an external tool to "sense" the external condition and I
> haven't found a way to directly translate that into something that effects
> what gets built (i.e. build foo if it's out of date OR if condition X is
Would something like this solve your problem?
import modules ;
actions quietly do-nothing
# creates a target which will be updated iff condition
# evaluates to true.
rule condition ( name : condition ? )
if ! $(condition)
# create a blank target which is always up to date
alias $(name) ;
# create a target which will always be out of date
# because the updating action never creates the
# corresponding file
make $(name) : : @do-nothing ;
# Note that this test can be anything
if --rebuild-foo in [ modules.peek : ARGV ]
rebuild-foo = true ;
condition foo-cond : $(rebuild-foo) ;
exe foo : a.cpp : <dependency>foo-cond ;
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