2009/2/23 Ralf Wildenhues <ralf.wildenh...@gmx.de>: > Hello Tavian, > > * Tavian Barnes wrote on Mon, Feb 23, 2009 at 06:22:12AM CET: >> EXTRA_PROGRAMS = generate >> generate_SOURCES = generate.c >> >> generated.c: generate > > BTW, the prerequisite here would need to be generate$(EXEEXT).
Oh, right. >> ./generate$(EXEEXT) >$@ >> >> bin_PROGRAMS = lookup >> lookup_SOURCES = lookup.c generated.c > > You need to use BUILT_SOURCES, and fake dependencies so that no > distributed file depends on an undistributed one. Untested: > > EXTRA_PROGRAMS = generate > BUILT_SOURCES = generate$(EXEEXT) > generated.c: generate.c Makefile.in > ./generate$(EXEEXT) >$@ > bin_PROGRAMS = lookup > lookup_SOURCES = lookup.c generated.c Great, thanks! >> This is almost right, but because generated.c gets distributed but >> `generate' doesn't, make sees generated.c as out-of-date in the >> tarballs, and re-builds it. This is worse when `make distcheck' is >> run, because of the VPATH build; $@ isn't even the right location to >> write to, > > generated.c can live in the source or in the build tree. But given that > different make implementations have slightly different VPATH semantics, > it may be useful to require it to always live in the source tree; > further, it may be useful to update it lazily (this shouldn't matter for > read-only trees iff your dependencies are set up correctly, but it > should make for faster rebuilds): > > $(srcdir)/generated.c: generate.c Makefile.in > ./generate$(EXEEXT) > tmp-generated.c > if diff tmp-generated.c $@ >/dev/null 2>&1; then \ > rm -f tmp-generated.c; \ > else \ > mv -f tmp-generated.c $@; \ > fi > > lookup_SOURCES = lookup.c $(srcdir)/generated.c I've got it living in $(srcdir) now, thanks. I can't see why your version of a lazy update would speed it up though. It still runs ./generate, and now it's running diff too, right? >> and the source directory is read-only anyway, so a qualified >> path wouldn't help. Is there any way to not build the `generate' >> target if generated.c exists, but still build it when it doesn't? > > Hope that helps. > > Cheers, > Ralf > It did. Thanks again. -- Tavian Barnes
