Re: Order-only prerequisites for emacs documentation

> Date: Wed, 29 Apr 2026 19:22:24 +0000
> From: Heime <[email protected]>
> 
> 
> 
> I notice that Makefile.in includes ${buildinfodir} as order-only prerequisites.
> Why is this, why is it important?

Because directory time stamps are not reliable.  See the excplanation
of this in the node "Prerequisite Types" of the GNU Make manual.

> Should one do the same for other documentation?

Only if the target file is placed in another directory that might not
yet exist.

> $(buildinfodir)/emacs.info: ${EMACSSOURCES} | ${buildinfodir}
> 	$(AM_V_GEN)$(MAKEINFO) $(MAKEINFO_OPTS) $(INFO_OPTS) -o $@ $<
> 
> But for emacs.dvi and emacs.pdf, ${buildinfodir} is not used.  What is the reason?

Because they are produced in the current directory, which always
exists.