Question

I am trying to compile with make. I have source in two directories, src and altsrc. I want make to look in altsrc for source files first, and then in src. I want the objects to go into directory obs. The relevant parts of my Makefile looks like:
VPATH=altsrc:src:obj

$(A_OUT): $(OBS)
    $(FORTRAN) -o $(A_OUT) $(OBS) $(LFLAGS)

obs/%.o: %.f
    $(FORTRAN) $(FFLAGS) $< -o $@

This Makefile actually compiles the code OK, but it has one really obnoxious side effect: It finds each source file (and there are alot) and copies them out of altsrc or src into the directory where I am running make. This is really annoying and leads to a bunch of confusion later on. I haven’t found any documentation anywhere that says this should be an effect of the VPATH macro. Can anyone tell me how to solve this? Thanks.

Answer 1

The trouble is that Make is RCS-savvy, and will check to see if a source file (e.g. td.f) can and should be updated from RCS. Yes, Make knows how to use co. If the source file isn’t in such an archive (such as the source files in altsrc), then Make shrugs and gets on with the work.

The quickest, dirtiest solution is to use make -r. This will disable the built-in rules, which should solve the problem nicely… unless you rely on the built-in rules elsewhere.

If that won’t do, you can override that particular rule with a do-nothing rule of your own, or with a rule that actually updates the sources in place, or you can touch the sources so that Make won’t consider them out of date, or put the RCS files someplace where Make can’t see them, or maybe two or three other options.