array_size.h (916B)
1 /* CC0 (Public domain) - see LICENSE file for details */ 2 #ifndef CCAN_ARRAY_SIZE_H 3 #define CCAN_ARRAY_SIZE_H 4 #include "config.h" 5 #include "build_assert.h" 6 7 /** 8 * ARRAY_SIZE - get the number of elements in a visible array 9 * @arr: the array whose size you want. 10 * 11 * This does not work on pointers, or arrays declared as [], or 12 * function parameters. With correct compiler support, such usage 13 * will cause a build error (see build_assert). 14 */ 15 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + _array_size_chk(arr)) 16 17 #if HAVE_BUILTIN_TYPES_COMPATIBLE_P && HAVE_TYPEOF 18 /* Two gcc extensions. 19 * &a[0] degrades to a pointer: a different type from an array */ 20 #define _array_size_chk(arr) \ 21 BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(typeof(arr), \ 22 typeof(&(arr)[0]))) 23 #else 24 #define _array_size_chk(arr) 0 25 #endif 26 #endif /* CCAN_ALIGNOF_H */