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warnings with libcurl.m4 and autoconf 2.68

From: Dave Reisner <>
Date: Sun, 20 Mar 2011 22:02:24 -0400

Hi all,

I'm using libcurl's m4 macro file (docs/libcurl/libcurl.m4) to ease
integration into a project I'm working on. With autoconf 2.68, the
following warning is thrown when running the pre-configure bootstrap:

+ autoconf warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call
detected in body
../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
../../lib/autoconf/general.m4:2660: _AC_LINK_IFELSE is expanded from...
../../lib/autoconf/general.m4:2677: AC_LINK_IFELSE is expanded from...
../../lib/m4sugar/m4sh.m4:605: AS_IF is expanded from...
../../lib/autoconf/general.m4:2030: AC_CACHE_VAL is expanded from...
../../lib/autoconf/general.m4:2051: AC_CACHE_CHECK is expanded from...
m4/libcurl.m4:38: LIBCURL_CHECK_CONFIG is expanded from... the top level

The whole suite that we call is:

aclocal -I m4 --install
automake --foreign

The above warning is thrown for each step. I've traced it to the
specific call in the m4 file (starting @ line 194) which is:

           AC_LINK_IFELSE(AC_LANG_PROGRAM([#include <curl/curl.h>],[
/* Try and use a few common options to force a failure if we
* are
   missing symbols or can't link. */
int x;

According to a post I found [1], AC_LANG_SOURCE has to be used to avoid
these sort of warnings, but the doc [2] states that AC_LANG_PROGRAM uses
AC_LANG_SOURCE, so it should be implicitly satisfied.

This doesn't seem to harm anything -- the project configures and builds
quite nicely with curl, but I'd like to be able to clean up these
warnings if at all possible. I'm not at all familiar with autotools, so
any insight would be greatly appreciated.

thanks from a happy libcurler,


List admin:
Received on 2011-03-21