/*
   attrs.h - wrapper macros for the gcc __attribute__(()) directive

   Copyright (C) 2007 Arthur de Jong

   This library 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 2.1 of the License, or (at your option) any later version.

   This library 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 library; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301 USA
*/

#ifndef _COMPAT_ATTRS_H
#define _COMPAT_ATTRS_H 1

/* These are macros to use some gcc-specific flags in case the're available
   and otherwise define them to empty strings. This allows us to give
   the compiler some extra information. */

#if __GNUC__ >= 3

/* this is used to flag function parameters that are not used in the function
   body. */
#define UNUSED(x)   x __attribute__((__unused__))

/* this is used to add extra format checking to the function calls as if this
   was a printf()-like function */
#define LIKE_PRINTF(format_idx,arg_idx) \
                    __attribute__((__format__(__printf__,format_idx,arg_idx)))

/* indicates that the function is "pure": it's result is purely based on
   the parameters and has no side effects or used static data */
#define PURE        __attribute__((__pure__))

/* the function's return value should be used by the caller */
#define MUST_USE    __attribute__((__warn_unused_result__))

/* the function returns a new data structure that has been freshly
   allocated */
#define LIKE_MALLOC __attribute__((__malloc__))

#else /* not __GNUC__ */

#define UNUSED(x)   x
#define LIKE_PRINTF(format_idx,arg_idx) /* no attribute */
#define PURE        /* no attribute */
#define MUST_USE    /* no attribute */
#define LIKE_MALLOC /* no attribute */

#endif /* not __GNUC__ */

#endif /* not _COMPAT_ATTRS_H */