1 /* $NetBSD: d_bltinoffsetof.c,v 1.3 2024/01/09 23:46:54 rillig Exp $ */ 2 # 3 "d_bltinoffsetof.c" 3 4 struct foo { 5 union { 6 struct { 7 struct { 8 int a; 9 int b; 10 } first; 11 char *second; 12 } s; 13 unsigned char padding[1000]; 14 } u; 15 union { 16 int a; 17 double b; 18 } array[50]; 19 }; 20 21 typedef int first[-(int)__builtin_offsetof(struct foo, u.s.first)]; 22 typedef int first_a[-(int)__builtin_offsetof(struct foo, u.s.first.a)]; 23 /* expect+1: ... (-4) ... */ 24 typedef int first_b[-(int)__builtin_offsetof(struct foo, u.s.first.b)]; 25 /* expect+1: ... (-8) ... */ 26 typedef int second[-(int)__builtin_offsetof(struct foo, u.s.second)]; 27 28 /* expect+1: ... (-1000) ... */ 29 typedef int array[-(int)__builtin_offsetof(struct foo, array)]; 30 /* expect+1: ... (-1000) ... */ 31 typedef int array_0_a[-(int)__builtin_offsetof(struct foo, array[0].a)]; 32 /* expect+1: ... (-1000) ... */ 33 typedef int array_0_b[-(int)__builtin_offsetof(struct foo, array[0].b)]; 34 /* expect+1: ... (-1008) ... */ 35 typedef int array_1_a[-(int)__builtin_offsetof(struct foo, array[1].a)]; 36 37 // There is no element array[50], but pointing right behind the last element 38 // may be fine. 39 /* expect+1: ... (-1400) ... */ 40 typedef int array_50_a[-(int)__builtin_offsetof(struct foo, array[50].a)]; 41 /* expect+1: ... (-1400) ... */ 42 typedef int sizeof_foo[-(int)sizeof(struct foo)]; 43 44 45 // 51 is out of bounds, as it is larger than the size of the struct. 46 // No warning though, maybe later. 47 /* expect+1: ... (-1408) ... */ 48 typedef int array_51_a[-(int)__builtin_offsetof(struct foo, array[51].a)]; 49