Yup, that's why the eq macro one is better: make -f and.mk A=22 B=44 > Crude AND Demo: > TRUE: A is 2, B is 4 > Macro-based AND Demo: > FALSE: A is 22, B is 44 >
The crude one fails because as you noticed, it considers 2, 22 and 222 to all be the same. That's why the macro also reverses the subst and tries to subst 22 into 2 which obviously catches the problem: $(if $(1:$(2)=),,$(if $(2:$(1)=),,T)) .... note the second $(if) I am not sure about eq with lists, though. Perhaps it has some problem there? Cheers, Tim 2008/6/17 Martin Dorey <[EMAIL PROTECTED]>: > Try make -f and.mk A=22 B=44. > > > ------------------------------ > > *From:* [EMAIL PROTECTED] [mailto: > bug-make-bounces+mdorey <bug-make-bounces%2Bmdorey>[EMAIL PROTECTED] *On > Behalf Of *Tim Murphy > *Sent:* Tuesday, June 17, 2008 09:31 > *To:* bug-make@gnu.org > *Subject:* Re: Help : how to use $(or condition ) & $(and condition ) > inmakefile > > > > Hi, > > > I have amended an example of how to use $(and) that I posted earlier for > Rakesh. I have tested this on Linux with make 3.81. > > It shows a crude way and a slightly more sophisticated way to use $(and) in > an if statement to determine if two variables have equal values: > > A=2 > B=4 > > # do "equal" by seeing if a subst returns the empty string: > A_is_2:=$(if $(subst 2,,$(A)),,T) > B_is_4:=$(if $(subst 4,,$(B)),,T) > > AandB:=$(and $(A_is_2),$(B_is_4)) > > # then you could do something based on this: > $(info Crude AND Demo: ) > ifneq ($(AandB),) > $(info TRUE: A is 2, B is 4) > else > $(info FALSE: A is $(A), B is $(B)) > endif > > > # One could make it look nicer by making an equals macro: > define eq > $(if $(1:$(2)=),,$(if $(2:$(1)=),,T)) > endef > > # which you could use as follows: > > $(info Macro-based AND Demo: ) > ifneq ($(and $(call eq,$(A),2),$(call eq,$(B),4)),) > $(info TRUE: A is 2, B is 4) > # do what you want to do when A=2 and B=4 > else > $(info FALSE: A is $(A), B is $(B)) > endif > > > > The output looks like this: > > > [EMAIL PROTECTED] base]make -f and.mk A=1 B=5 > Crude AND Demo: > FALSE: A is 1, B is 5 > Macro-based AND Demo: > FALSE: A is 1, B is 5 > make: *** No targets. Stop. > > > > > [EMAIL PROTECTED] base]make -f and.mk A=2 B=4 > Crude AND Demo: > TRUE: A is 2, B is 4 > Macro-based AND Demo: > TRUE: A is 2, B is 4 > make: *** No targets. Stop. > > > > > [EMAIL PROTECTED] base]make -f and.mk A=2 B=3 > Crude AND Demo: > FALSE: A is 2, B is 3 > Macro-based AND Demo: > FALSE: A is 2, B is 3 > make: *** No targets. Stop. > > > > 2008/6/6 Paul Smith <[EMAIL PROTECTED]>: > > On Fri, 2008-06-06 at 05:05 -0700, rakesh aggarwal wrote: > > But still there is some problem. > > I haven't looked at your example. > > But, the very first thing to check is the version of GNU make you're > using (make --version). If it's not 3.81, then the manual you're > reading is not the right one for the version of GNU make you're using. > > -- > > ------------------------------------------------------------------------------- > Paul D. Smith <[EMAIL PROTECTED]> Find some GNU make tips at: > http://www.gnu.org http://make.mad-scientist.us > "Please remain calm...I may be mad, but I am a professional." --Mad > Scientist > > > > > -- > You could help some brave and decent people to have access to uncensored > news by making a donation at: > > http://www.thezimbabwean.co.uk/ > -- You could help some brave and decent people to have access to uncensored news by making a donation at: http://www.thezimbabwean.co.uk/
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