Richard W.M. Jones wrote: > On Thu, Nov 24, 2011 at 03:01:03PM +0000, Paul Howarth wrote: >> http://marc.info/?l=pptpclient-devel&m=132102054518031 > > This is indeed rather unexpected behaviour of make! > > BTW I think your patch is incomplete, since it will create an > incomplete config.h if the disk runs out of space. I think this would > be better, and should also avoid the parallel make problem: > > config.h: > echo "/* text added by Makefile target config.h */" > $@-t > echo "#define PPTP_LINUX_VERSION \"$(VERSION)$(RELEASE)\"" >> $@-t > echo "#define PPPD_BINARY \"$(PPPD)\"" >> $@-t > echo "#define IP_BINARY \"$(IP)\"" >> $@-t > mv $@-t $@ Yes, that is better and does solve the problem. Here's a good rule I've been following since I was first burned by this: "never redirect directly to a Makefile target". (where "target" means $@ or any literal that is equivalent). That means redirect output to a temporary file like Rich did above, and only when that process is known to have succeeded do you rename the temporary file to $@. However, I would volunteer some additional suggestions: - use a {...} group (cheaper than a (...) subshell) so we redirect only once; that reduces the duplication of the "$@-t", and eliminates the dichotomy of the initial "> $@-t", while all subsequent ones are ">> $@-t". - use outer single quotes so you don't have to backslash-escape the inner double quote chars. less syntax is more maintainable. - make the file read-only, so it is clearer that it is generated, and thus harder to change accidentally. The only down-side to this part is that you then have to be careful to remove any preexisting $@ or $@-t, since redirecting onto a read-only file will often fail. config.h: rm -f $@ $@-t; \ { \ echo '/* text added by Makefile target config.h */'; \ echo '#define PPTP_LINUX_VERSION "$(VERSION)$(RELEASE)"'; \ echo '#define PPPD_BINARY "$(PPPD)"'; \ echo '#define IP_BINARY "$(IP)"'; \ } > $@-t && chmod a-w $@-t && mv $@-t $@ -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
