On Tue, 10 May 2005, Sam Ravnborg wrote: > On Mon, May 09, 2005 at 10:19:01AM -0500, Kumar Gala wrote: > > > > On May 6, 2005, at 6:22 PM, <cpclark at xmission.com> wrote: > > > > >On Fri, 6 May 2005, Kumar Gala wrote: > > > > I tried the following w/o success: > > > > > > > > $(obj)/uImage: $(obj)/vmlinux.gz > > > > $(Q)rm -f $@ > > > > $(call if_changed,uimage) > > > > @echo ' Image: $@' $(shell if [ -f $@ ]; then echo 'is ready'; > > > > else echo 'not made'; fi) > > > > > >Couldn't you eliminate the ($shell ..) construct altogether, like this?: > > > > > >$(obj)/uImage: $(obj)/vmlinux.gz > > > $(Q)rm -f $@ > > > $(call if_changed,uimage) > > > @echo -n '? Image: $@' > > > @if [ -f $@ ]; then echo 'is ready' ; else echo 'not made'; fi > > > > Yes, and this seems to actually work. > > > > Sam, does this look reasonable to you. If so I will work up a patch. > > Looks ok - but I do not see why use of $(shell ...) did not work out.
As I understand it, the $(shell ...) construct doesn't "work" in the case cited above because make evaluates/expands the $(shell ...) stuff while it is parsing the makefile and building the command list--i.e. before it has issued any commands to build anything. What seems to be desired in this case is a file-existence test which runs "inline" with respect to the preceding commands. The use of $(shell ...) inside a command subverts/preempts that natural sequence. I think. :-) Chris
