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Re: autoconf-2.68: no AC_LANG_SOURCE call detected in body
From: |
Eric Blake |
Subject: |
Re: autoconf-2.68: no AC_LANG_SOURCE call detected in body |
Date: |
Thu, 23 Sep 2010 07:52:17 -0600 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100907 Fedora/3.1.3-1.fc13 Mnenhy/0.8.3 Thunderbird/3.1.3 |
On 09/23/2010 06:56 AM, Ralf Corsepius wrote:
Hi,
I am facing a new issue/regression with autoconf-2.68:
That is not a regression, but a feature. Reread NEWS:
AC_COMPILE_IFELSE([
#ifndef FOO
choke me
#endif
])
You should have used:
AC_COMPILE_IFELSE([AC_LANG_SOURCE([
#ifndef FOO
choke me
#endif
])
With older autoconfs, autoreconf remains entirely silent.
Not only were they entirely silent, but most likely generated a broken
configure. If you don't use AC_LANG_SOURCE, then you don't get the
benefit of all the prior AC_DEFINEs being implicitly included before the
body of your test, which leads to documented cases of mis-diagnosing
whether a feature is present for a given build.
What is wrong with this configure.ac rsp. how to overcome these warnings?
Use AC_LANG_SOURCE, like the warning told you to do in the first place.
--
Eric Blake address@hidden +1-801-349-2682
Libvirt virtualization library http://libvirt.org