Restructuring the automake and autoconf packages

Charles Wilson cwilson@ece.gatech.edu
Sun Dec 2 23:11:00 GMT 2001


Brett Porter wrote:
> 
> > No.  The new path setting is only good for *called*
> > processes in the
> > same fork/exec chain.  The parent shell's PATH is
> > not modified, so once
> > 'autoconf' finishes and you drop back into your
> > interactive shell, your
> > old PATH is back in effect.
> >
> 
> Sorry, I must have misunderstood. The message said it
> EXPORTs the var - but I haven't yet looked at the
> scripts themselves (later) - I assumed it exported it
> back to the shell so you could not call the wrapper.
>

No, in the context of shells, 'export' means that subshells will inherit
the value (it does NOT mean that parent shell will "inherit" anything). 
If you *don't* export, then the subprocesses WON'T see the new value at
all, and the new PATH is only valid within the current script -- but not
within called scripts, and probably not even within exec'ed scripts
because the #!/bin/sh of the exec'ed script will start up a new
subshell...

> > Yeah, I understand.  Alternatively, you can argue:
> > assume that everyone
> > has up to date tools.  Therefore, if you want older
> > versions, you must
> > AC_PREREQ them.  (Note that our 'devel' tree is
> > actually the official
> > stable current release, and our 'stable' tree is
> > actually the 'old and
> > out of date' release.)
> >
> 
> I thought that was a funny naming when I read it, but
> I can't think of a better one. How about "ancient" and
> "current"? :)
> 
> The reason for my argument is that I thought AC_PREREQ
> was a >= relationship. ie if you PREREQ(2.13), then
> anything higher is OK.

But that's precisely the thing that is NOT true here.  You *can't* use
autoconf-2.50 with a 2.13-based configure.in without changes.  So,
AC_PREREQ(X) == 'stable' if X <= 2.13, 'devel' if X > 2.13.  The only
remaining case is X undefined, which I (arbitrarily) mapped to 'devel'.

> I don't know how it is
> implemented (bad me, never used it myself) - but even
> this wouldn't make a lot of sense as 2.52 isn't
> backwards compatible.

Bingo.

> Like I said, food for thought. Probably not worth
> debating though.

BTW, I'm confused.  I never got the original message "Restructioning the
automake and autoconf packages" in my inbox.  I can't find it in the
cygwin, cygwin-announce, or cygwin-developers archives.  Brett, where
did you see the original message to which you initially replied?  Did I
just lose some email cause of the ATT problems?

--Chuck

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