I look at both solutions mentioned and learned a bit more about what I am dealing with.
Basically it is possible for a.idl to internally reference b.idl. In this case, part of the generated aC.h file includes bC.h. So if I mode the file and create a new bC_modded.h file, aC.h does not reference it. So basically, What I really need to do is as part of the implicit rule, do something like what Mr Shal suggests : %C.h $S.h $C.cpp $S.cpp : $.idl <invoke idl compiler> Mr Shal's Is as_modded exists, check code, replacing the %C.h as appropriate. I think this should work. Since All changes to the %C.h are within the rule to generate it. Thanks for the input Dale Pennington _______________________________________________ Help-make mailing list Help-make@gnu.org http://lists.gnu.org/mailman/listinfo/help-make