Re: Issues with subdir-objects and differing versions of automake

[Stefano Lattarini]

On 08/26/2013 03:30 PM, Shawn Webb wrote:
> Hey All,
Hi Shawn, sorry for the delay.

> I'm working on ClamAV and am restructuring our autoconf/automake
> scripts to be a bit more organized and modernized. On one machine, I
> have automake 1.14 installed.. On another, much older machine, I have
> automake 1.11.1 installed.
>
> Quick history of why I'm emailing: ClamAV's codebase has a lot of
> different programs to build inside of it (clamd, clamdscan, clamscan,
> freshclam, clamconf, among others). Each of these programs have code
> shared between them. The shared code was placed inside of the "shared"
> directory. We weren't using the subdir-objects automake option, but it
> appears that option is now mandatory with automake 1.14. So I added
> that option in. Automake didn't like me simply adding that option in,
> so after a bit of research, I decided to convert the shared code
> folder into building a shared library (called libclamshared.la) that
> will get statically compiled into each of these programs.
>
A suggestion: if this is a non-installed convenience library that you
are only using to static-link into your program, you can simply use a
libfoo.a archive library (use the _LIBRARIES primary instead of the
_LTLIBRARIES one), and avoid all the complications, slowdown and extra
dependencies associated with the use of libtool.

> I then
> removed all references to each of the C files in the shared directory
> for each of these projects and instead added the shared object to be
> statically linked in.
>
> Even after all this work, automake 1.14 still requires me to use the
> subdir-objects option. That's fine.
>
Actually, it doesn't.  It just warns you that if you don't do so, you
might have unexpected breakage in future automake versions.  But for
all the versions in the 1.* series (inclusing 1.14), automake should
keep working fine (and in a backward-compatible way) without the
subdir-objects option being specified; the only difference being the
warning you are seeing.  See also below.

> All make targets work in automake
> 1.14. Everything works as expected with automake 1.14 with
> subdir-objects enabled. If I remove subdir-objects, then autoreconf
> errors and tells me that using subdir-objects is now required. So
> removing the subdir-objects option is not an option for me; the option
> is required.
>
> The problem comes when I try to use automake 1.11.1. The distclean
> make target is broken with automake 1.11.1 when the subdir-objects
> option is included. Compilation succeeds, which is good. Everything
> works perfectly if I don't include the option.
So, at this point, you have two ways to proceed:

  1. Don't use the subdir-objects option, and live with the warning
     for the moment.  But keep in mind that you will have to convert
     to the use of that option once you switch to Automake 2.0; so
     be prepared, but until then, no big deal.

  2. Just require that developers working with your project use
     automake >= 1.14 (or even 1.13, in case that doesn't suffer
     of the issue you are seeing in 1.11).  Automake is easy and
     quick to install, and has few dependencies.

I'd suggest you go with option (2), as developing with two versions
of automake that have been release four years apart doesn't make much
sense to me.  But that is only a suggestion: option (1) should be
completely viable.

> So I'm stuck in this in-limbo state where automake 1.14 requires
> subdir-objects, but the distclean target doesn't work in 1.11.1 when
> the option is enabled.
>
> What're my options? I'll admit that I'm a complete newb to autotools
> and it's very possible that I'm doing something wrong. I've included
> below my Makefile.am for clamd.
>
> Thanks,
>
> Shawn Webb
HTH,
  Stefano