Re: make question (target dependent variable)

[Paul D. Smith]

%% "James" <hslee@ind.alcatel.com> writes:

  j> P = pp qq
  j> T = pp rr
  j> CFLAGS = -c
  j> ifneq ($(strip $(foreach f,$(P),$(findstring $(f),$@))),)
  j> CFLAGS += -g
  j> endif

  j> .PHONY: $(T)
  j> all: $(T)
  j> $(T):
  j>         @echo $@ $(CFLAGS)

Well, you haven't used any target-specific variable settings here so... ??

This makefile is confused.  You cannot have a line like this:

  j> ifneq ($(strip $(foreach f,$(P),$(findstring $(f),$@))),)

and have it make any sense.  The value $@ is an automatic variable: it
has a value ONLY in the context of running a particular rule, but here
you're using it in a preprocessor statement (ifneq), which is expanded
as the makefile is read in... at that time $@ has no value and so it's
replaced with the empty string.  Thus, your test will never be true as
it's looking for $(f) in a constant empty string.

Not to mention you don't want to use findstring here, since this:

    $(findstring foo.o,barfoo.o)

will return true (or, really, "foo.o") when you expect it to return
false (empty).  You should be using filter and/or filter-out here, as
those test entire words not just substrings.


Why don't you just say:
  P = pp qq
  T = pp rr
  CFLAGS = -c

  .PHONY: $(T)
  all: $(T)
  $(P): CFLAGS += -g
  $(T):
          @echo $@ $(CFLAGS)

That gives a rule for all targets in variable T, and it sets all targets
in variable P to have a target-specific variable "CFLAGS += -g", which
is I think what you wanted.

-- 
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 Paul D. Smith <psmith@gnu.org>          Find some GNU make tips at:
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