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/* Copyright 2025-2026 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 2.1 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 <https://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2025. */
#ifndef _@GUARD_PREFIX@_STDCOUNTOF_H
#if __GNUC__ >= 3
@PRAGMA_SYSTEM_HEADER@
#endif
@PRAGMA_COLUMNS@
/* The include_next requires a split double-inclusion guard. */
#if (defined __cplusplus ? @CXX_HAVE_STDCOUNTOF_H@ : @HAVE_STDCOUNTOF_H@)
# @INCLUDE_NEXT@ @NEXT_STDCOUNTOF_H@
#else
#ifndef _@GUARD_PREFIX@_STDCOUNTOF_H
#define _@GUARD_PREFIX@_STDCOUNTOF_H
/* This file uses _GL_GNUC_PREREQ. */
#if !_GL_CONFIG_H_INCLUDED
#error "Please include config.h first."
#endif
/* Get size_t. */
#include <stddef.h>
/* Returns the number of elements of the array A, as a value of type size_t.
Example declarations of arrays:
extern int a[];
extern int a[10];
static int a[10][20];
void func () { int a[10]; ... }
Attempts to produce an error if A is a pointer, e.g. in
void func (int a[10]) { ... }
*/
#define countof(...) \
((size_t) (sizeof (__VA_ARGS__) / sizeof (__VA_ARGS__)[0] \
+ 0 * _gl_verify_is_array (__VA_ARGS__)))
/* Attempts to verify that A is an array. */
#if defined __cplusplus
/* Borrowed from verify.h. */
# if !GNULIB_defined_struct__gl_verify_type
template <int w>
struct _gl_verify_type {
unsigned int _gl_verify_error_if_negative: w;
};
# define GNULIB_defined_struct__gl_verify_type 1
# endif
# if __cplusplus >= 201103L
# if 1
/* Use decltype. */
/* Default case. */
template <typename T>
struct _gl_array_type_test { static const int is_array = -1; };
/* Unbounded arrays. */
template <typename T>
struct _gl_array_type_test<T[]> { static const int is_array = 1; };
/* Bounded arrays. */
template <typename T, size_t N>
struct _gl_array_type_test<T[N]> { static const int is_array = 1; };
/* String literals. */
template <typename T, size_t N>
struct _gl_array_type_test<T const (&)[N]> { static const int is_array = 1; };
# define _gl_verify_is_array(...) \
sizeof (_gl_verify_type<_gl_array_type_test<decltype(__VA_ARGS__)>::is_array>)
# else
/* Use template argument deduction.
Use sizeof to get a constant expression from an unknown type.
Note: This approach does not work for countof (((int[]) { a, b, c })). */
/* Default case. */
template <typename T>
struct _gl_array_type_test { double large; };
/* Unbounded arrays. */
template <typename T>
struct _gl_array_type_test<T[]> { char small; };
/* Bounded arrays. */
template <typename T, size_t N>
struct _gl_array_type_test<T[N]> { char small; };
/* The T& parameter is essential here: it prevents decay (array-to-pointer
conversion). */
template <typename T> _gl_array_type_test<T> _gl_array_type_test_helper(T&);
# define _gl_verify_is_array(...) \
sizeof (_gl_verify_type<(sizeof (_gl_array_type_test_helper(__VA_ARGS__)) < sizeof (double) ? 1 : -1)>)
# endif
# else
/* The compiler does not have the necessary functionality. */
# define _gl_verify_is_array(...) 0
# endif
#else
/* In C, we can use typeof and __builtin_types_compatible_p. */
/* Work around clang bug <https://github.com/llvm/llvm-project/issues/143284>. */
# if _GL_GNUC_PREREQ (3, 1) && ! defined __clang__ /* || defined __clang__ */
# define _gl_verify_is_array(...) \
sizeof (struct { unsigned int _gl_verify_error_if_negative : __builtin_types_compatible_p (typeof (__VA_ARGS__), typeof (&*(__VA_ARGS__))) ? -1 : 1; })
# else
/* The compiler does not have the necessary built-ins. */
# define _gl_verify_is_array(...) 0
# endif
#endif
#endif /* _@GUARD_PREFIX@_STDCOUNTOF_H */
#endif
#endif /* _@GUARD_PREFIX@_STDCOUNTOF_H */
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