1  /* The array_length and array_end macros.
       2     Copyright (C) 2017-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef _ARRAY_LENGTH_H
      20  #define _ARRAY_LENGTH_H
      21  
      22  /* array_length (VAR) is the number of elements in the array VAR.  VAR
      23     must evaluate to an array, not a pointer.  */
      24  #define array_length(var)                                               \
      25    (sizeof (var) / sizeof ((var)[0])                                     \
      26     + 0 * sizeof (struct {                                               \
      27         _Static_assert (!__builtin_types_compatible_p                    \
      28                         (__typeof (var), __typeof (&(var)[0])),          \
      29                         "argument must be an array");                    \
      30     }))
      31  
      32  /* array_end (VAR) is a pointer one past the end of the array VAR.
      33     VAR must evaluate to an array, not a pointer.  */
      34  #define array_end(var) (&(var)[array_length (var)])
      35  
      36  #endif /* _ARRAY_LENGTH_H */