Re: building templates

[Paul D. Smith]

%% Martin Kleinschmidt <address@hidden> writes:

  mk> I have files xaaa.F, xbbb.F, which contain C preprocessor
  mk> directives.  From each of these files, i want to generate
  mk> different objects by passing different variables to the C
  mk> preprocessor.  e.g. I want to generate zaaa.o and daaa.o from
  mk> xaaa.F, and zbbb.o and dbbb.o from xbbb.F There will be multiple
  mk> x???.F files but from each x???.F I will need to generate at most
  mk> 4 (probably only 2) different objects.

  mk> so what I did:

  mk> writing it explicitly:

  mk> ZWHICH = -DMY_Z
  mk> zaaa.f: xaaa.F
  mk>         $(CC) -E -P $(ZWHICH) $< -o $@

  mk> and subsequently applying the standard rules for %.o:%.f

  mk> I thought of doing something like

  mk> z%.f: x%.F
  mk>         $(CC) -E -P $(ZWHICH) $< -o $@

  mk> but that would break all other z*.o (which do not depend on an x???.F)
  mk> Okay - I could place my templates in a separate directory, but 
  mk> a) I don't want that and 
  mk> b) I want to learn something about makefiles :-)

  mk> I tried:

  mk> ZOBJS = zaaa.o zbbb.o
  mk> $(foreach object, $(ZOBJS), $(eval \
  mk> $(object): $(patsubst z%.o, x%.F, $(object)) \
  mk>         $(CC) $(PREFLAG) $(ZWHICH) $< -o $@))

No, this won't work.  You don't have any newlines here first of all, so
the whole output will appear on one line.  Replace "eval" with "warning"
to see what make sees:

$(foreach object, $(ZOBJS), $(warning \
$(object): $(patsubst z%.o, x%.F, $(object)) \
         $(CC) $(PREFLAG) $(ZWHICH) $< -o $@))

(the $(warning ...) function is handy for this).


Anyway, eval is very much overkill for this: you just need static
pattern rules.  Try:

  ZOBJS = zaaa.o zbbb.o

  $(patsubst %.o,%.f,$(ZOBJS)) : %.f : %.F
           $(CC) -E -P $(ZWHICH) $< -o $@

-- 
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 Paul D. Smith <address@hidden>          Find some GNU make tips at:
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