<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8"> <META NAME="GENERATOR" CONTENT="GtkHTML/3.32.2"> </HEAD> <BODY> On Wed, 2011-06-01 at 08:44 -0700, Alan Coopersmith wrote: <BLOCKQUOTE TYPE=CITE> <PRE> On 06/ 1/11 04:42 AM, Gaetan Nadon wrote: > On Tue, 2011-05-31 at 23:59 -0700, Jeremy Huddleston wrote: >> AC_LANG_DEFINES_PROVIDED seems to be only in newer, GPLv3, versions of autoconf ... is there a way around this? > > I looked at it yesterday, using AC_LANG_SOURCE should be the right thing to do > (some examples in the server). For things where we actually compile source, yes, but for the RAW_CPP macro, I was trying to avoid it, since it adds additional text to the input to cpp, which may or may not throw off our testing. I'd prefer something more like (untested): m4_ifdef([AC_LANG_DEFINES_PROVIDED], [AC_LANG_DEFINES_PROVIDED]) </PRE> </BLOCKQUOTE> That's the first thing I tried. Looking up in the doc, they cannot really say why one would need AC_LANG_DEFINES_PROVIDED and that it should be very rare. I just tried with/without AC_LANG_SOURCE and both test files are identical: <BLOCKQUOTE> <BLOCKQUOTE> <PRE> /* confdefs.h */ #define PACKAGE_NAME "libX11" #define PACKAGE_TARNAME "libX11" #define PACKAGE_VERSION "1.4.3" #define PACKAGE_STRING "libX11 1.4.3" #define PACKAGE_BUGREPORT "<A HREF="https://bugs.freedesktop.org/enter_bug.cgi?product=xorg">https://bugs.freedesktop.org/enter_bug.cgi?product=xorg</A>" #define PACKAGE_URL "" #define STDC_HEADERS 1 #define HAVE_SYS_TYPES_H 1 #define HAVE_SYS_STAT_H 1 #define HAVE_STDLIB_H 1 #define HAVE_STRING_H 1 #define HAVE_MEMORY_H 1 #define HAVE_STRINGS_H 1 #define HAVE_INTTYPES_H 1 #define HAVE_STDINT_H 1 #define HAVE_UNISTD_H 1 #define __EXTENSIONS__ 1 #define _ALL_SOURCE 1 #define _GNU_SOURCE 1 #define _POSIX_PTHREAD_SEMANTICS 1 #define _TANDEM_SOURCE 1 #define PACKAGE "libX11" #define VERSION "1.4.3" #define HAVE_DLFCN_H 1 #define LT_OBJDIR ".libs/" #define PACKAGE_VERSION_MAJOR 1 #define PACKAGE_VERSION_MINOR 4 #define PACKAGE_VERSION_PATCHLEVEL 3 /* end confdefs.h.  */ Does cpp redefine unix ? </PRE> </BLOCKQUOTE> </BLOCKQUOTE> lang.m4 in 2.67 (which does not call AC_LANG_DEFINES_PROVIDED): <BLOCKQUOTE> <PRE> # AC_LANG_SOURCE(BODY) # -------------------- # Produce a valid source for the current language, which includes the # BODY, and as much as possible `confdefs.h'. AC_DEFUN([AC_LANG_SOURCE], [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_SOURCE()(BODY) # ---------------------- # Default implementation of AC_LANG_SOURCE. m4_define([AC_LANG_SOURCE()], [$1]) </PRE> </BLOCKQUOTE> lang.m4 in 2.68. Note the call to AC_LANG_DEFINES_PROVIDED <BLOCKQUOTE> <PRE> # AC_LANG_SOURCE(BODY) # -------------------- # Produce a valid source for the current language, which includes the # BODY, and as much as possible `confdefs.h'. AC_DEFUN([AC_LANG_SOURCE], [AC_LANG_DEFINES_PROVIDED[]_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_SOURCE()(BODY) # ---------------------- # Default implementation of AC_LANG_SOURCE. m4_define([AC_LANG_SOURCE()], [$1]) </PRE> </BLOCKQUOTE> Although not clear in the docs, you should use AC_LANG_DEFINES_PROVIDED if you cannot inline conftest in your test program. In our case, it has always been inlined before when the module was configured with autoconf 2.63b and up: <BLOCKQUOTE> <PRE> As of Autoconf 2.63b, the source file also contains the results of all of the <TT>AC_DEFINE</TT> performed so far. </PRE> # AC_LANG_CONFTEST(BODY) # ---------------------- # Save the BODY in `conftest.$ac_ext'.  Add a trailing new line. AC_DEFUN([AC_LANG_CONFTEST], [m4_pushdef([_AC_LANG_DEFINES_PROVIDED],   [m4_warn([syntax], [$0: no AC_LANG_SOURCE call detected in body])])]dnl [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]dnl [[]_AC_LANG_DEFINES_PROVIDED[]m4_popdef([_AC_LANG_DEFINES_PROVIDED])]) # AC_LANG_CONFTEST()(BODY) # ------------------------ # Default implementation of AC_LANG_CONFTEST. # This version assumes that you can't inline confdefs.h into your # language, and as such, it is safe to blindly call # AC_LANG_DEFINES_PROVIDED.  Language-specific overrides should # remove this call if AC_LANG_SOURCE does inline confdefs.h. m4_define([AC_LANG_CONFTEST()], [cat > conftest.$ac_ext <<_ACEOF AC_LANG_DEFINES_PROVIDED[]$1 _ACEOF]) </BLOCKQUOTE> Had there been an issue with inlining contest, we would have found out quite a while ago. The inlining was introduced in 2.63b, without anyone noticing. I think it is safe to use AC_LANG_SOURCE. It has the merit of being consistent with other configuration tests and prevents a workaround that always need to be explained. </BODY> </HTML>