Eric Blake wrote:
> However, the spurious output is still
> misleading, so what do you think of this patch to clean it up? I have not
> pushed it yet...
>
> A variable with _cv_ in the name is still cached, regardless of whether
> you used AC_CACHE_VAL; all AC_CACHE_VAL does is wrap additional logic to
> produce output, thus it should not be used in situations where you don't
> want the side effect of output.
"AC_CACHE_VAL does is wrap additional logic to produce output" - that is
something that may be valid in the current autoconf. But the documentation
of AC_CACHE_VAL is clear about the fact that it is the AC_CACHE_VAL
invocation that ensures the caching of the variable. The fact that - currently -
a variable with _cv_ in its name is cached even without an AC_CACHE_VAL
invocation is undocumented; you might even say that it's a bug. Therefore I
find it unwise to rely on that.
I'm applying this instead. It also relies on an undocumented detail (the
as_echo_n variable), but it will be less hairy to fix if it breaks in
future versions of autoconf.
2009-02-27 Bruno Haible <br...@clisp.org>
Avoid spurious "(cached)" in configure output.
* m4/gnulib-common.m4 (gl_CACHE_VAL_SILENT): New macro.
* m4/ceil.m4 (gl_FUNC_CEIL_LIBS): Use it instead of AC_CACHE_VAL.
* m4/ceilf.m4 (gl_FUNC_CEILF_LIBS): Likewise.
* m4/ceill.m4 (gl_FUNC_CEILL_LIBS): Likewise.
* m4/floor.m4 (gl_FUNC_FLOOR_LIBS): Likewise.
* m4/floorf.m4 (gl_FUNC_FLOORF_LIBS): Likewise.
* m4/floorl.m4 (gl_FUNC_FLOORL_LIBS): Likewise.
* m4/stdarg.m4 (gl_STDARG_H): Likewise.
Reported by Eric Blake.
--- m4/gnulib-common.m4.orig 2009-02-27 18:24:00.000000000 +0100
+++ m4/gnulib-common.m4 2009-02-27 18:19:19.000000000 +0100
@@ -1,4 +1,4 @@
-# gnulib-common.m4 serial 10
+# gnulib-common.m4 serial 11
dnl Copyright (C) 2007-2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -109,3 +109,16 @@
[
AC_C_BIGENDIAN
])
+
+# gl_CACHE_VAL_SILENT(cache-id, command-to-set-it)
+# is like AC_CACHE_VAL(cache-id, command-to-set-it), except that it does not
+# output a spurious "(cached)" mark in the midst of other configure output.
+# This macro should be used instead of AC_CACHE_VAL when it is not surrounded
+# by an AC_MSG_CHECKING/AC_MSG_RESULT pair.
+AC_DEFUN([gl_CACHE_VAL_SILENT],
+[
+ saved_as_echo_n="$as_echo_n"
+ as_echo_n=':'
+ AC_CACHE_VAL([$1], [$2])
+ as_echo_n="$saved_as_echo_n"
+])
--- m4/ceil.m4.orig 2009-02-27 18:24:00.000000000 +0100
+++ m4/ceil.m4 2009-02-27 18:23:12.000000000 +0100
@@ -1,5 +1,5 @@
-# ceil.m4 serial 2
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# ceil.m4 serial 3
+dnl Copyright (C) 2007, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
@@ -18,7 +18,7 @@
# Sets CEIL_LIBM.
AC_DEFUN([gl_FUNC_CEIL_LIBS],
[
- AC_CACHE_VAL([gl_cv_func_ceil_libm], [
+ gl_CACHE_VAL_SILENT([gl_cv_func_ceil_libm], [
gl_cv_func_ceil_libm=?
AC_TRY_LINK([
#ifndef __NO_MATH_INLINES
--- m4/ceilf.m4.orig 2009-02-27 18:24:00.000000000 +0100
+++ m4/ceilf.m4 2009-02-27 18:21:10.000000000 +0100
@@ -1,5 +1,5 @@
-# ceilf.m4 serial 3
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# ceilf.m4 serial 4
+dnl Copyright (C) 2007, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
@@ -34,7 +34,7 @@
# Sets CEILF_LIBM.
AC_DEFUN([gl_FUNC_CEILF_LIBS],
[
- AC_CACHE_VAL([gl_cv_func_ceilf_libm], [
+ gl_CACHE_VAL_SILENT([gl_cv_func_ceilf_libm], [
gl_cv_func_ceilf_libm=?
AC_TRY_LINK([
#ifndef __NO_MATH_INLINES
--- m4/ceill.m4.orig 2009-02-27 18:24:00.000000000 +0100
+++ m4/ceill.m4 2009-02-27 18:21:49.000000000 +0100
@@ -1,5 +1,5 @@
-# ceill.m4 serial 3
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# ceill.m4 serial 4
+dnl Copyright (C) 2007, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
@@ -34,7 +34,7 @@
# Sets CEILL_LIBM.
AC_DEFUN([gl_FUNC_CEILL_LIBS],
[
- AC_CACHE_VAL([gl_cv_func_ceill_libm], [
+ gl_CACHE_VAL_SILENT([gl_cv_func_ceill_libm], [
gl_cv_func_ceill_libm=?
AC_TRY_LINK([
#ifndef __NO_MATH_INLINES
--- m4/floor.m4.orig 2009-02-27 18:24:00.000000000 +0100
+++ m4/floor.m4 2009-02-27 18:22:54.000000000 +0100
@@ -1,5 +1,5 @@
-# floor.m4 serial 2
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# floor.m4 serial 3
+dnl Copyright (C) 2007, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
@@ -18,7 +18,7 @@
# Sets FLOOR_LIBM.
AC_DEFUN([gl_FUNC_FLOOR_LIBS],
[
- AC_CACHE_VAL([gl_cv_func_floor_libm], [
+ gl_CACHE_VAL_SILENT([gl_cv_func_floor_libm], [
gl_cv_func_floor_libm=?
AC_TRY_LINK([
#ifndef __NO_MATH_INLINES
--- m4/floorf.m4.orig 2009-02-27 18:24:00.000000000 +0100
+++ m4/floorf.m4 2009-02-27 18:20:44.000000000 +0100
@@ -1,5 +1,5 @@
-# floorf.m4 serial 3
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# floorf.m4 serial 4
+dnl Copyright (C) 2007, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
@@ -34,7 +34,7 @@
# Sets FLOORF_LIBM.
AC_DEFUN([gl_FUNC_FLOORF_LIBS],
[
- AC_CACHE_VAL([gl_cv_func_floorf_libm], [
+ gl_CACHE_VAL_SILENT([gl_cv_func_floorf_libm], [
gl_cv_func_floorf_libm=?
AC_TRY_LINK([
#ifndef __NO_MATH_INLINES
--- m4/floorl.m4.orig 2009-02-27 18:24:00.000000000 +0100
+++ m4/floorl.m4 2009-02-27 18:21:31.000000000 +0100
@@ -1,5 +1,5 @@
-# floorl.m4 serial 3
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# floorl.m4 serial 4
+dnl Copyright (C) 2007, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
@@ -34,7 +34,7 @@
# Sets FLOORL_LIBM.
AC_DEFUN([gl_FUNC_FLOORL_LIBS],
[
- AC_CACHE_VAL([gl_cv_func_floorl_libm], [
+ gl_CACHE_VAL_SILENT([gl_cv_func_floorl_libm], [
gl_cv_func_floorl_libm=?
AC_TRY_LINK([
#ifndef __NO_MATH_INLINES
--- m4/stdarg.m4.orig 2009-02-27 18:24:00.000000000 +0100
+++ m4/stdarg.m4 2009-02-27 18:22:29.000000000 +0100
@@ -1,5 +1,5 @@
-# stdarg.m4 serial 2
-dnl Copyright (C) 2006, 2008 Free Software Foundation, Inc.
+# stdarg.m4 serial 3
+dnl Copyright (C) 2006, 2008-2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
@@ -46,7 +46,7 @@
else
dnl Provide a substitute in <config.h>, either __va_copy or as a simple
dnl assignment.
- AC_CACHE_VAL([gl_cv_func___va_copy], [
+ gl_CACHE_VAL_SILENT([gl_cv_func___va_copy], [
AC_TRY_COMPILE([#include <stdarg.h>], [
#ifndef __va_copy
error, bail out
