Re: A not so clear behaviour for Makefiles including other makefiles

[Paul D. Smith]

%% Noel Yap <address@hidden> writes:

  ny> "Paul D. Smith" wrote:

  >> The second make starts from scratch, with no memory or information
  >> about the previous make (or even that there _WAS_ a previous make)
  >> or what it did or didn't do.

  ny> Is there any way of passing information to the exec'ed make (eg by
  ny> setting environment variables or something)?

Not currently.  The re-exec code doesn't go through the normal "put
exported make variables to the environment" processing that's done
before a shell is invoked... and I think it's correct to work that way,
otherwise code like:

  ifndef FOO
     FOO = $(BAR)
     export FOO
  endif

wouldn't work properly, if the rebuilt makefile impacted the value of
BAR.


However, this is probably worth requesting as a new feature: some way to
tell whether or not you've re-execed.  I would assume it would be
something like MAKELEVEL, except for counting re-execs.  That way people
could conditionalize on that where they wanted to.  It has to be
carefully done though to be sure the variable is set where it should be
and _NOT_ set where it shouldn't be.

-- 
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