Re: referencing top_srcdir/top_builddir in an autoconf test?

[Eric Blake]

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According to Monty Taylor on 5/13/2009 1:32 PM:

Hello Monty, and sorry for the delay,

>>> Obviously would need a -I${top_srcdir}. I'm fine with hacking that in to
>>> the test - except there doesn't seem to be an available autoconf
>>> variable I can use to fill in the value of top_srcdir in that context.
>> You can use $srcdir, and some other variables documented in
>>   info Autoconf "Configuration Actions"
> 
> AWESOME. Exactly what I was looking for.
> 
>> Maybe the manual should state that they're also available during the
>> execution of configure, as opposed to only at config.status time.
> 
> Perhaps ... it certainly was not evident to me when looking through the
> manual that I should have looked in that section.

Does this help?

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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>From 58cbe7b1eade23c6106a0180e75d87b1cc1967b3 Mon Sep 17 00:00:00 2001
From: Eric Blake <address@hidden>
Date: Fri, 10 Jul 2009 06:11:24 -0600
Subject: [PATCH] Document that $srcdir can be used during configure.

* doc/autoconf.texi (Preset Output Variables): Add a paragraph.
* THANKS: UPdate.
Reported by Monty Taylor.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog         |    7 +++++++
 doc/autoconf.texi |    9 ++++++++-
 2 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d256710..6fb2622 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2009-07-10  Eric Blake  <address@hidden>
+
+       Document that $srcdir can be used during configure.
+       * doc/autoconf.texi (Preset Output Variables): Add a paragraph.
+       * THANKS: UPdate.
+       Reported by Monty Taylor.
+
 2009-07-09  Eric Blake  <address@hidden>

        Fix test typo.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 3528f53..2fefd58 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -2180,7 +2180,6 @@ Configuration Actions
 The name of the top source directory, assuming that the working
 directory is the current build directory.

-
 @item ac_top_build_prefix
 The name of the top build directory, assuming that the working
 directory is the current build directory.
@@ -2332,6 +2331,14 @@ Preset Output Variables
 precious variables (@pxref{Setting Output Variables},
 @code{AC_ARG_VAR}).

+The preset variables which are available during @file{config.status}
+(@pxref{Configuration Actions}) may also be used during
address@hidden tests.  For example, it is permissible to reference
address@hidden when constructing an option @option{-I} list of include
+directories.  When used in this manner, coupled with the fact that
address@hidden is always run from the top build directory, it is
+sufficient to use just @samp{$srcdir} instead of @samp{$top_srcdir}.
+
 @c Just say no to ASCII sorting!  We're humans, not computers.
 @c These variables are listed as they would be in a dictionary:
 @c actor
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