%% "Derick" <[EMAIL PROTECTED]> writes:
d> Hello... I was wondering if anyone could give me some insight
d> (==help). I am writing a makefile that has a SINGLE command that
d> generates multiple output files. The difficulty I am running into
d> is that the command is executed for each dependency, where the
d> command actually takes care of all of them in one run.
d> Specifically (simplified greatly):
d> all: MyStuff.a
d> GENERATED_CXX=MyStuff.cpp MyStuff_skel.cpp
d> $(GENERATED_CXX) : MyStuff.idl
d> $(IDLGEN) $(IDLGENFLAGS) $<
That's what this syntax is defined to do; multiple targets in a single
rule don't specify all are made from a single invocation, they specify
that each target can be built using the same script (but individual
invocations).
IOW, this:
foo bar: baz
some command
is just syntactic sugar for this:
foo: baz
some command
bar: baz
some command
See the GNU make manual.
d> with the usual %.o:%.cpp rule elsewhere. What ends up happening is that
d> $(IDLGEN) is run twice (once for MyStuff.cpp, once for MyStuff_skel.cpp),
d> where I only want it done once.
You have to use pattern rules for this. GNU make (and only GNU
make) has a special feature where multiple patterns on the left-hand
side of a pattern rule means that a single invocation of the command
creates all the targets at once, just as you want:
%.cpp %_skel.cpp : %.idl
$(IDLGEN) $(IDLGENFLAGS) $<
all: MyStuff.a
GENERATED_CXX=MyStuff.cpp MyStuff_skel.cpp
MyStuff.a : $(GENERATED_CXX:.cpp=.o)
# archive them here
will do what you want.
Again, see the GNU make manual.
--
-------------------------------------------------------------------------------
Paul D. Smith <[EMAIL PROTECTED]> Find some GNU make tips at:
http://www.gnu.org http://www.paulandlesley.org/gmake/
"Please remain calm...I may be mad, but I am a professional." --Mad Scientist
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