include/array_length.h - master - githubmirror/glibc

include/array_length.h
50 строк2 KB
Paul Eggert
Update copyright dates with scripts/update-copyrights
02 янв 2026, 00:42
02 янв 2026, 00:4266f3e92
/* The array_length and array_end macros.
   Copyright (C) 2017-2026 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C 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.

   The GNU C 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 the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _ARRAY_LENGTH_H
#define _ARRAY_LENGTH_H

/* array_length (VAR) is the number of elements in the array VAR.  VAR
   must evaluate to an array, not a pointer.  */
#define array_length(var)                                               \
  (sizeof (var) / sizeof ((var)[0])                                     \
   + 0 * sizeof (struct {                                               \
       _Static_assert (!__builtin_types_compatible_p                    \
                       (__typeof (var), __typeof (&(var)[0])),          \
                       "argument must be an array");                    \
   }))

/* array_end (VAR) is a pointer one past the end of the array VAR.
   VAR must evaluate to an array, not a pointer.  */
#define array_end(var) (&(var)[array_length (var)])

/* array_foreach (PTR, ARRAY) iterates over all the elements in an
   array, assigning the locally defined pointer variable PTR to each
   element in turn.

   array_foreach_const (PTR, ARRAY) does the same, but *PTR is declared
   const even if the array is not. */
#define array_foreach(ptr, array)                                      \
  for (__typeof ((array)[0]) *ptr = (array) ;			       \
       ptr < array_end (array) ; ptr++)

#define array_foreach_const(ptr, array)                                \
  for (const __typeof ((array)[0]) *ptr = (array) ;		       \
       ptr < array_end (array) ; ptr++)

#endif /* _ARRAY_LENGTH_H */