Re: target-specific object files

[Ted Stern]

Thanks everyone!

I went with the test on MAKECMDGOALS.  I had done something like this years
ago but my make muscles got rusty.

To digress slightly, I also had a situation where I needed an include file
that was generated from a subdirectory that needed to be built by the
makefile.

I solved it by forcing a re-read of prerequisites using a generated
touchfile that was included at the bottom of the Makefile with no text in
it:

For example:



all:  foo/.touch $(OTHEREXES)

test: all

foo/.touch:  foo/.
<tab>   git submodule update --init --recursive $(@D)
<tab>   cd $(@D); git checkout master; git pull; touch $(@F)

special.o:  generated.h
generated.h:  foo/path/to/generator.source

# ... other prereqs ...

-include foo/.touch


Ted

On Wed, Nov 18, 2015 at 12:00 AM, Rakesh Sharma <address@hidden>
wrote:

> What you are asking for can be accomplished using ifeq conditionals, like
> as shown below:
>
>
> SHELL := /bin/sh
>
> WHO_AM_I = $(CURDIR)/$(word 1,$(MAKEFILE_LIST))
>
>      CC = g++
>  CFLAGS = -Wall
> LDFLAGS =
>
> EXESUFF =
> SRC         = a.cpp
> OBJS       = a$(EXESUFF).o
> RUNFILE = b$(EXESUFF).out
>
> all : $(RUNFILE)
>
> $(RUNFILE) : $(OBJS)
> $(CC) $(CFLAGS) $(LDFLAGS) $(OBJS)  $(LIBS) -o $@
>
> $(OBJS) : $(SRC)
> $(CC) -c $(CFLAGS) $< -o $@
>
> clean :
> /bin/rm -f ./*.o ./*.out
>
> TESTFLAG := _test
> test: CFLAGS += -D__TEST__
> ifeq ($(EXESUFF),$(TESTFLAG))
> test: $(RUNFILE)
> else
> test:
> @$(MAKE) --no-print-directory -f $(WHO_AM_I) $@ EXESUFF=$(TESTFLAG)
> endif
>
>
> Alternatively, you can use the second expansion facility provided by GNU
> make to achieve the same results:
>
>
> .SECONDEXPANSION:
> TESTFLAG := _test
> test: CFLAGS += -D__TEST__
> test: $$(if $$(EXESUFF),$$(RUNFILE),)
> $(if $(EXESUFF),,@$(MAKE) --no-print-directory -f $(WHO_AM_I) $@
> EXESUFF=$(TESTFLAG))
>
> -Rakesh
>
>
>
> > Hello Paul et al.,
>
> > I'm familiar with target-specific variables and have been using them for
> > many years.
>
> > But they don't seem to be doing what I want in one circumstance -- I want
> > to build different target names depending on an inherited target-specific
> > variable.
>
> > For example
>
> > EXESUFF =#   blank to start
>
> > a$(EXESUFF).o : a.cpp
> > <tab> $(CXX) $(CXXFLAGS) -c $< -o $@
>
> > OBJS = a$(EXESUFF).o
>
> > b$(EXESUFF).out : $(OBJS)
> > <tab> $(CXX) $(CXXFLAGS) $(LDFLAGS) $(OBJS) $(LIBS) -o $@
>
> > all:   b.out
>
> > clean:
> > <tab> /bin/rm *.o *.out
>
> > test:   EXESUFF = _test
> > test:   CXXFLAGS += -D__TEST__
>
> > % make all
>
> > (builds a.o and b.out)
>
> > % make clean; make test
>
> > (builds a.o and b.out -- but I want it to build a_test.o and b_test.out)
>
> > Is there a way to do what I want?
>
> > Thanks,
>
> > Ted
>
>