new module 'unused-parameter'

[Bruno Haible]

Eric Blake wrote:
> > Therefore my proposal is to
> >   - create a new module 'unused-parameter', that inserts a definition of
> >     _GL_UNUSED_PARAMETER_ in a header file, like 'link-warning' and 'arg-
> nonnull'
> >     do,
> >   - update unistr.h accordingly.
> 
> Sounds reasonable.  But I'd rather see _GL_UNUSED_PARAMETER than 
> _GL_UNUSED_PARAMETER_

This implements the module, and makes unistr.h work again for libunistring.


2009-12-24  Bruno Haible  <address@hidden>

        New module 'unused-parameter'.
        * build-aux/unused-parameter.h: New file, extracted from earlier
        gnulib-common.m4.
        * modules/unused-parameter: New file.
        * lib/unistr.h: Include unused-parameter.h.
        (u32_mbtouc_unsafe, u32_mbtouc): Use _GL_UNUSED_PARAMETER instead of
        _GL_UNUSED.
        * modules/unistr/base (Depends-on): Add unused-parameter.

======================== build-aux/unused-parameter.h ========================
/* A C macro for declaring that specific function parameters are not used.
   Copyright (C) 2008-2009 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published
   by the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* _GL_UNUSED_PARAMETER is a marker that can be appended to function parameter
   declarations for parameters that are not used.  This helps to reduce
   warnings, such as from GCC -Wunused-parameter.  The syntax is as follows:
       type param _GL_UNUSED_PARAMETER
   or more generally
       param_decl _GL_UNUSED_PARAMETER
   For example:
       int param _GL_UNUSED_PARAMETER
       int *(*param)(void) _GL_UNUSED_PARAMETER
   Other possible, but obscure and discouraged syntaxes:
       int _GL_UNUSED_PARAMETER *(*param)(void)
       _GL_UNUSED_PARAMETER int *(*param)(void)
 */
#ifndef _GL_UNUSED_PARAMETER
# if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
#  define _GL_UNUSED_PARAMETER __attribute__ ((__unused__))
# else
#  define _GL_UNUSED_PARAMETER
# endif
#endif
========================== modules/unused-parameter ==========================
Description:
A C macro for declaring that specific function parameters are not used.

Applicability:
all

Files:
build-aux/unused-parameter.h

Depends-on:

configure.ac:

Makefile.am:
# The BUILT_SOURCES created by this Makefile snippet are not used via #include
# statements but through direct file reference. Therefore this snippet must be
# present in all Makefile.am that need it. This is ensured by the applicability
# 'all' defined above.

BUILT_SOURCES += unused-parameter.h
# The unused-parameter.h that gets inserted into generated .h files is the same
# as build-aux/unused-parameter.h, except that it has the copyright header cut
# off.
unused-parameter.h: $(top_srcdir)/build-aux/unused-parameter.h
        $(AM_V_GEN)rm -f address@hidden $@ && \
        sed -n -e '/GL_UNUSED_PARAMETER/,$$p' \
          < $(top_srcdir)/build-aux/unused-parameter.h \
          > address@hidden && \
        mv address@hidden $@
MOSTLYCLEANFILES += unused-parameter.h unused-parameter.h-t

UNUSED_PARAMETER_H=unused-parameter.h

Include:

License:
LGPLv2+

Maintainer:
Bruno Haible
==============================================================================
--- lib/unistr.h.orig   Fri Dec 25 02:40:04 2009
+++ lib/unistr.h        Fri Dec 25 02:07:02 2009
@@ -19,6 +19,9 @@
 
 #include "unitypes.h"
 
+/* Get common macros for C.  */
+#include "unused-parameter.h"
+
 /* Get bool.  */
 #include <stdbool.h>
 
@@ -183,7 +186,8 @@
        u32_mbtouc_unsafe (ucs4_t *puc, const uint32_t *s, size_t n);
 # else
 static inline int
-u32_mbtouc_unsafe (ucs4_t *puc, const uint32_t *s, size_t n _GL_UNUSED)
+u32_mbtouc_unsafe (ucs4_t *puc,
+                   const uint32_t *s, size_t n _GL_UNUSED_PARAMETER)
 {
   uint32_t c = *s;
 
@@ -253,7 +257,7 @@
        u32_mbtouc (ucs4_t *puc, const uint32_t *s, size_t n);
 # else
 static inline int
-u32_mbtouc (ucs4_t *puc, const uint32_t *s, size_t n _GL_UNUSED)
+u32_mbtouc (ucs4_t *puc, const uint32_t *s, size_t n _GL_UNUSED_PARAMETER)
 {
   uint32_t c = *s;
 
--- modules/unistr/base.orig    Fri Dec 25 02:40:04 2009
+++ modules/unistr/base Fri Dec 25 01:48:44 2009
@@ -6,6 +6,7 @@
 
 Depends-on:
 unitypes
+unused-parameter
 stdbool
 inline