determining prerequisite & dependent targets

[gk]

I need to be able to determine the list of prerequisites, or dependent 
targets, for any given target.

In my system, a single makefile approach is used, which includes many 
makefiles. All targets (excluding phony targets) have an absolute path.

I have been using the following rules which work pretty well but I am not 
happy with this approach because it depends on parsing the output of make 
-p. If that output formatting ever changes, these rules will break.

I would like to know if there is a better way or how difficult would it be 
to add such a query feature to make, via command line options or any other 
tricks for accessing makes internal database directly.
Thanks.

# Makefile

.PHONY: FORCE
$(CURDIR)/foo1: $(CURDIR)/foo2
$(CURDIR)/foo1: $(CURDIR)/foo3
$(CURDIR)/foo2: $(CURDIR)/foo3

$(CURDIR)/foo%:
        @echo $@

# echo the prerequisites of target /%
reqs./%: FORCE
	@$(MAKE) -p /$* 2>/dev/null|sed -n -e 's%^/$(patsubst .,\.,$*): 
\(.*\)%\1%p' -e '\%^/$(patsubst .,\.,$*):.*%q'

# echo the dependents of target /%
deps./%: FORCE
	@$(MAKE)   -p /$* 2>/dev/null|sed -n 's%^\(/.*\):.* /$(patsubst 
.,\.,$*)\b.*%\1%p'

#eof



address@hidden junk]$ make reqs.$(pwd -P)/foo1
/usr/local/apache/htdocs/common/test/junk/foo2 
/usr/local/apache/htdocs/common/test/junk/foo3
address@hidden junk]$ make reqs.$(pwd -P)/foo2
/usr/local/apache/htdocs/common/test/junk/foo3
address@hidden junk]$ make reqs.$(pwd -P)/foo3
address@hidden junk]$ make deps.$(pwd -P)/foo1
address@hidden junk]$ make deps.$(pwd -P)/foo2
/usr/local/apache/htdocs/common/test/junk/foo1
address@hidden junk]$ make deps.$(pwd -P)/foo3
/usr/local/apache/htdocs/common/test/junk/foo1
/usr/local/apache/htdocs/common/test/junk/foo2
address@hidden junk]$

- Greg Keraunen
http://www.xmake.org