From: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
Date: Mon, 19 Jul 2010 17:59:19 +0000 (+0200)
Subject: Allow inspecting AC_PREPROC_IFELSE output in true branch.
X-Git-Tag: v2.67~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2fd37d5d0ac2c4f85ba17ab32e52a855e3d002c4;p=thirdparty%2Fautoconf.git

Allow inspecting AC_PREPROC_IFELSE output in true branch.

* lib/autoconf/general.m4 (_AC_PREPROC_IFELSE_BODY): Redirect
preprocessor output to conftest.i rather than /dev/null.
(_AC_PREPROC_IFELSE): Remove conftest.i in the postprocessing.
* tests/compile.at (Order of user actions and cleanup): Extend
test in the ACTION-IF-TRUE branch.
* doc/autoconf.texi (Running the Preprocessor): Document new
feature.
* NEWS: Update.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
---

diff --git a/ChangeLog b/ChangeLog
index 01a854af..43aebcc9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
 2010-07-19  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
 
+	Allow inspecting AC_PREPROC_IFELSE output in true branch.
+	* lib/autoconf/general.m4 (_AC_PREPROC_IFELSE_BODY): Redirect
+	preprocessor output to conftest.i rather than /dev/null.
+	(_AC_PREPROC_IFELSE): Remove conftest.i in the postprocessing.
+	* tests/compile.at (Order of user actions and cleanup): Extend
+	test in the ACTION-IF-TRUE branch.
+	* doc/autoconf.texi (Running the Preprocessor): Document new
+	feature.
+	* NEWS: Update.
+
 	Fix AC_FC_LIBRARY_LDFLAGS detection for BlueGene xlf -qipa.
 	* lib/autoconf/fortran.m4 (_AC_FC_LIBRARY_LDFLAGS): Ignore
 	'-link', added spuriously when -qipa is used with the XL
diff --git a/NEWS b/NEWS
index a0228811..97c5495d 100644
--- a/NEWS
+++ b/NEWS
@@ -10,6 +10,9 @@ GNU Autoconf NEWS - User visible changes.
 
 ** New macro AC_FC_LINE_LENGTH to accept long Fortran source code lines.
 
+** AC_PREPROC_IFELSE now keeps the preprocessed output in the conftest.i
+   file for inspection by the commands in the ACTION-IF-TRUE argument.
+
 * Major changes in Autoconf 2.66 (2010-07-02) [stable]
   Released by Eric Blake, based on git versions 2.65.*.
 
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 4202108f..be7e3ef5 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -8900,7 +8900,8 @@ This macro uses @code{CPPFLAGS}, but not @code{CFLAGS}, because
 preprocessors.
 
 It is customary to report unexpected failures with
-@code{AC_MSG_FAILURE}.
+@code{AC_MSG_FAILURE}.  If needed, @var{action-if-true} can further access
+the preprocessed output in the file @file{conftest.i}.
 @end defmac
 
 For instance:
diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index fc4905b7..5706d695 100644
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -2461,7 +2461,7 @@ AC_DEFUN([AC_RUN_LOG],
 # Shell function body for _AC_PREPROC_IFELSE.
 m4_define([_AC_PREPROC_IFELSE_BODY],
 [  AS_LINENO_PUSH([$[]1])
-  AS_IF([_AC_DO_STDERR([$ac_cpp conftest.$ac_ext]) >/dev/null && {
+  AS_IF([_AC_DO_STDERR([$ac_cpp conftest.$ac_ext]) > conftest.i && {
 	 test -z "$ac_[]_AC_LANG_ABBREV[]_preproc_warn_flag$ac_[]_AC_LANG_ABBREV[]_werror_flag" ||
 	 test ! -s conftest.err
        }],
@@ -2486,7 +2486,7 @@ AC_DEFUN([_AC_PREPROC_IFELSE],
   [$0_BODY])]dnl
 [m4_ifvaln([$1], [AC_LANG_CONFTEST([$1])])]dnl
 [AS_IF([ac_fn_[]_AC_LANG_ABBREV[]_try_cpp "$LINENO"], [$2], [$3])
-rm -f conftest.err[]m4_ifval([$1], [ conftest.$ac_ext])[]dnl
+rm -f conftest.err conftest.i[]m4_ifval([$1], [ conftest.$ac_ext])[]dnl
 ])# _AC_PREPROC_IFELSE
 
 # AC_PREPROC_IFELSE(PROGRAM, [ACTION-IF-TRUE], [ACTION-IF-FALSE])
diff --git a/tests/compile.at b/tests/compile.at
index b26d8101..e3e4e076 100644
--- a/tests/compile.at
+++ b/tests/compile.at
@@ -294,8 +294,8 @@ AT_DATA([configure.ac],
 [[AC_INIT
 AC_PROG_CC
 
-AC_PREPROC_IFELSE([AC_LANG_PROGRAM([int ok;], [])],
-		  [test -f conftest.err || AS_EXIT([1])],
+AC_PREPROC_IFELSE([AC_LANG_PROGRAM([int grepme;], [])],
+		  [{ test -f conftest.err && grep grepme conftest.i; } || AS_EXIT([1])],
 		  [AS_EXIT([1])])
 AC_PREPROC_IFELSE([AC_LANG_PROGRAM([#define 12 34 /*], [])],
 		  [AS_EXIT([1])],