According to Ralf Wildenhues on 3/2/2010 2:35 PM: > Second, I do think this is a regression, as our documentation > pretty clearly states that AC_LANG_SOURCE is the one expanding > all the AC_DEFINEs seen so far. I do however also think that > the old code was ugly and hackish. Not sure whether it would > be better to go back, or go forward and announce the API change. I'd rather go forward. In other words, I'm thinking of the patch below. Comments? > > But what I do know is that we need better macro coverage here. The change was made back on 2008-11-03 (commit 8e27cc7f5, contained in autoconf 2.63b), so although it is somewhat of a regression (AC_LANG_CONFTEST outputs defines now, when it did not do so previously), there obviously aren't that many packages that try to mix-and-match their own LANG_CONFTEST with autoconf's LANG_SOURCE, or we might have heard about this issue sooner. More test coverage is always welcome, but I'm okay with just documentation patches for 2.66. May I ask why LB_LANG_CONFTEST was created in the first place, rather than sticking with the autoconf interface, or is that decision lost in history? Might it have something to do with the (ancient) bug where we tried to output #line directives in the original conftest file corresponding to locations in configure, which was later withdrawn when it was determined that configure files often exceed 64k lines and it breaks some preprocessors to have #line numbers that large? -- Don't work too hard, make some time for fun as well! Eric Blake ebb9@xxxxxxx
From 3556636b84637d9ebb9e9118a20d92127d13a713 Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@xxxxxxxxxx>
Date: Tue, 2 Mar 2010 15:46:34 -0700
Subject: [PATCH] Document AC_LANG_CONFTEST semantic change.
* doc/autoconf.texi (Generating Sources) <AC_LANG_CONFTEST>:
Enhance documentation, to show that semantic change in 2.63b was
intentional.
* THANKS: Update.
Reported by Brian J. Murrell, analyzed by Ralf Wildenhues.
Signed-off-by: Eric Blake <eblake@xxxxxxxxxx>
---
ChangeLog | 7 +++++++
doc/autoconf.texi | 3 ++-
2 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 5aae86c..bc2a58b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2010-03-02 Eric Blake <eblake@xxxxxxxxxx>
+ Document AC_LANG_CONFTEST semantic change.
+ * doc/autoconf.texi (Generating Sources) <AC_LANG_CONFTEST>:
+ Enhance documentation, to show that semantic change in 2.63b was
+ intentional.
+ * THANKS: Update.
+ Reported by Brian J. Murrell, analyzed by Ralf Wildenhues.
+
Fix shell code in AS_TR_SH documentation.
* doc/autoconf.texi (Common Shell Constructs) <AS_TR_SH>: Fix
example to expand to valid shell code.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 8fca9ae..716422c 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -8651,7 +8651,8 @@ Generating Sources
@acindex{LANG_CONFTEST}
Save the @var{source} text in the current test source file:
@file{conftest.@var{extension}} where the @var{extension} depends on the
-current language.
+current language. As of Autoconf 2.63b, the source file also contains
+the results of all of the @code{AC_DEFINE} performed so far.
Note that the @var{source} is evaluated exactly once, like regular
Autoconf macro arguments, and therefore (i) you may pass a macro
--
1.6.6.1
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