make ignore_value more generic; deprecate ignore_ptr

[Jim Meyering]

Pádraig Brady wrote:
...
> Cool, thanks for doing that.
> It probably needs this too:
>
> #ifndef __attribute__
> /* The __attribute__((__deprecated__) feature
>    is available in gcc versions 3.1 and later.  */
> # if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 1)
> #  define __attribute__(Spec)   /* empty */
> # endif
> #endif

Thanks!  It needed a few other tweaks, too.
I'm Cc'ing bug-gnulib, now too, in case anyone there can improve on this.
It's in your name, so I'll wait for an "ok" before pushing it.

[ For newcomers, the quick summary is that Pádraig found a way to
  unify ignore_value and ignore_ptr.  Here's the context:
  http://marc.info/?t=129391563400002&r=1&w=2 ]

>From 1e47005f2eac55ad241d17a1711895c2e6ab3f64 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <address@hidden>
Date: Wed, 5 Jan 2011 12:09:52 +0100
Subject: [PATCH] ignore-value: make ignore_value more generic; deprecate 
ignore_ptr

* lib/ignore-value.h: Include <stdint.h>, for decl of intptr_t.
(ATTRIBUTE_DEPRECATED): Define.
(_ignore_case): New function.
(ignore_value): New macro, to replace the old function.
(ignore_ptr): Arrange for any use to evoke a deprecation warning.
* modules/ignore-value (Depends-on): Add stdint.
---
 ChangeLog            |   11 +++++++++++
 lib/ignore-value.h   |   25 +++++++++++++++++++++----
 modules/ignore-value |    1 +
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6a6198b..f068683 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2011-01-05  Pádraig Brady <address@hidden>
+       and Jim Meyering  <address@hidden>
+
+       ignore-value: make ignore_value more generic; deprecate ignore_ptr
+       * lib/ignore-value.h: Include <stdint.h>, for decl of intptr_t.
+       (ATTRIBUTE_DEPRECATED): Define.
+       (_ignore_case): New function.
+       (ignore_value): New macro, to replace the old function.
+       (ignore_ptr): Arrange for any use to evoke a deprecation warning.
+       * modules/ignore-value (Depends-on): Add stdint.
+
 2011-01-04  Bruce Korb  <address@hidden>

        git-version-gen: avoid a sub-shell
diff --git a/lib/ignore-value.h b/lib/ignore-value.h
index 04d6520..8f60b0e 100644
--- a/lib/ignore-value.h
+++ b/lib/ignore-value.h
@@ -15,9 +15,9 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

-/* Written by Jim Meyering.  */
+/* Written by Jim Meyering and Pádraig Brady.  */

-/* Use these functions to avoid a warning when using a function declared with
+/* Use "ignore_value" to avoid a warning when using a function declared with
    gcc's warn_unused_result attribute, but for which you really do want to
    ignore the result.  Traditionally, people have used a "(void)" cast to
    indicate that a function's return value is deliberately unused.  However,
@@ -35,8 +35,25 @@
 #ifndef _GL_IGNORE_VALUE_H
 # define _GL_IGNORE_VALUE_H

-static inline void ignore_value (int i) { (void) i; }
-static inline void ignore_ptr (void* p) { (void) p; }
+# include <stdint.h>
+
+# ifndef ATTRIBUTE_DEPRECATED
+/* The __attribute__((__deprecated__)) feature
+   is available in gcc versions 3.1 and newer.  */
+#  if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 1)
+#   define ATTRIBUTE_DEPRECATED /* empty */
+#  else
+#   define ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
+#  endif
+# endif
+
+static inline void _ignore_value (intptr_t p) { (void) p; }
+# define ignore_value(x) _ignore_value ((intptr_t) x)
+
+/* ignore_value works for both scalars and pointers; deprecate ignore_ptr.  */
+static inline void ATTRIBUTE_DEPRECATED
+ignore_ptr (void *p) { (void) p; } /* deprecated: use ignore_value */
+
 /* FIXME: what about aggregate types? */

 #endif
diff --git a/modules/ignore-value b/modules/ignore-value
index 8d48863..aeda194 100644
--- a/modules/ignore-value
+++ b/modules/ignore-value
@@ -5,6 +5,7 @@ Files:
 lib/ignore-value.h

 Depends-on:
+stdint

 configure.ac:
 AC_REQUIRE([AC_C_INLINE])
--
1.7.3.4