Hi Philip, it looks like a good idea. Do you think it worths to be discussed with automake hackers?
Cheers, Giuseppe Philip Guenther <[email protected]> writes: > On Fri, Apr 11, 2008 at 2:45 PM, Giuseppe Scrivano<[email protected]> wrote: >> I could find on this ML archives only a thread about this subject: to >> consider the file checksum instead of the timestamp. >> Other systems like scons already support this feature and it would be >> great to have it for GNU Make too. > > This is a long dead thread (it's been sitting in my mailbox for a > year, ouch), but I'll throw in my two cents that a makefile can > implement this for itself with pattern rules. Consider: > > ---- > %.o: %.c > %.o.new: %.c > $(COMPILE.c) -o $@ $< > %.o: %.o.new > @{ [ -f [email protected] ] && md5sum -c --status [email protected]; } || \ > { md5sum $< >[email protected]; cp $< $@; } > > .SECONDARY: > ----- > > Poof, if you touch a .c file without making changes that affect the > compiler output, the executable will not be relinked. Indeed, the > presence of the .SECONDARY target means the only thing that will be > rerun each time is the md5sum. > > Yes, this is non-trivial to use, but it's also completely flexible, > letting you use whatever checksum comparison you want (need to strip > comments or RCS/CVS tags from the file before checksumming it? Sure!) > and can be used Right Now. > > Anyway, we now return you to your originally scheduled mailing list. > > > Philip Guenther _______________________________________________ Bug-make mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-make
