Re: AM_CONDITIONAL + AM_COND_IF does not work

[Marc Wäckerlin]

Hi Gavin

Thank you, that helps up to the next step ...

Am 09.03.2015 18:45, schrieb Gavin Smith:
> automake doesn't know or care that one of these uses of
> AC_CONFIG_FILES was conditional. It is looking for the input files to
> automake (like "Makefile.am"), which it will derive from the arguments
> to AC_CONFIG_FILES. It wouldn't be possible for these input files to
> be defined conditionally in the configure script, because logically
> automake runs before the configure script.

That's what I thought, so AM_COND_IF + AC_CONFIG_FILES only works for 
existing files, but not in my case. A limitation, that should be better 
documented ...

In my eyes, this behaviour is a bug, automake should not test, read or 
evaluate conditional files, if the condition does not match.


Now, is there a way to workaround that?

Your idea is a good approach:

> The automake manual says that automake won't recognize an argument to
> AC_CONFIG_FILES if its value is given indirectly through a shell
> variable (see "Requirements" node), so maybe you could try that.

It works, e.g. I always generate RPM spec files by filling in configure 
information:
------------------------------------------
AC_CONFIG_FILES([${PACKAGE_NAME}.spec])
------------------------------------------

That works great. But here, automake is not involved. Unfortunately, 
variables seem not to work, if automake is required. The code:
------------------------------------------
makefile=makefile
AM_CONDITIONAL([HAVE_SRC_DIR], [test -f src/${makefile}.am])
AM_COND_IF([HAVE_SRC_DIR], [AC_CONFIG_FILES([src/${makefile}])])
------------------------------------------
does not generate "src/makefile.in" by automake, as it should.

So, the meaning od the above mentioned manual text is: "variables don't 
work with automake" ... :(


Other ideas? Other solutions?

Am I the only one with dozens of similar projects who wants to save some 
typing ...? ;)




> On 9 March 2015 at 15:06, Marc Wäckerlin <address@hidden> wrote:
> > I try to generically find out, whether examples/makefile.am exists in 
> > a
> > project and to automatically use it, if it exists:
> > ------------------------------------------
> > AM_CONDITIONAL([HAVE_EXAMPLES_DIR], [test -f examples/makefile.am])
> > AM_COND_IF([HAVE_EXAMPLES_DIR], 
> > [AC_CONFIG_FILES([examples/makefile])])
> > ------------------------------------------

A note for those who did not understand the intention:

If and only if file "examples/makefile.am" exists, then it should be 
added to "AC_CONFIG_FILES". That means, it is possible and wanted 
behavior that "examples/makefile.am" does not exists, then it should 
simply not be added. So if "examples/makefile.am" does not exists, also 
"examples/makefile.in" will not exist.

The idea behind: I have a standard project setup, where examples, tests 
and other subdirectories are optional and I want to write a generic 
M4-file that scans for the existing makefiles and automatically adds 
those that exist.

So, yes the file does not exits, but no, it does not have to, since 
that's exactly the idea of the test: Find out if it exists and use it in 
case it exists.



Thank you
Regards
Marc
--
Marc Wäckerlin
http://marc.wäckerlin.ch