| @@ -1,7 +1,40 @@ | | | @@ -1,7 +1,40 @@ |
| 1 | /* $NetBSD: msg_329.c,v 1.1 2021/01/02 10:22:44 rillig Exp $ */ | | 1 | /* $NetBSD: msg_329.c,v 1.2 2021/01/24 17:44:37 rillig Exp $ */ |
| 2 | # 3 "msg_329.c" | | 2 | # 3 "msg_329.c" |
| 3 | | | 3 | |
| 4 | // Test for message: type '%s' is not a member of '%s' [329] | | 4 | // Test for message: type '%s' is not a member of '%s' [329] |
| 5 | | | 5 | |
| 6 | TODO: "Add example code that triggers the above message." | | 6 | union u { |
| 7 | TODO: "Add example code that almost triggers the above message." | | 7 | int i1; |
| | | 8 | int i2; |
| | | 9 | void *vp; |
| | | 10 | }; |
| | | 11 | |
| | | 12 | void |
| | | 13 | example(void) |
| | | 14 | { |
| | | 15 | /* |
| | | 16 | * A type cast to a union type is valid if the source type is any |
| | | 17 | * member type of the union. Since all union members with the same |
| | | 18 | * type have the same representation, the name of the union member |
| | | 19 | * doesn't matter. |
| | | 20 | * |
| | | 21 | * XXX: could there be padding bits or other tricky details that are |
| | | 22 | * settable per-member? These could make the type alone insufficient |
| | | 23 | * for determining the exact representation. |
| | | 24 | * |
| | | 25 | * C99 6.5.4 "Cast operators" does not mention a union cast. On the |
| | | 26 | * contrary, it says that the type name shall specify a scalar type. |
| | | 27 | * |
| | | 28 | * C11 6.5.4 "Cast operators" differs from C99 but still requires |
| | | 29 | * scalar types for both the target type and the source value. |
| | | 30 | * |
| | | 31 | * This is a GCC extension. |
| | | 32 | * See https://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html. |
| | | 33 | * |
| | | 34 | * FIXME: lint says in message 328 that "union cast is a C9X feature", |
| | | 35 | * but that is wrong. It is a GCC feature. |
| | | 36 | */ |
| | | 37 | union u u_i1 = (union u)3; |
| | | 38 | union u u_vp = (union u)(void *)0; |
| | | 39 | union u u_cp = (union u)(char *)0; /* expect: 329 */ |
| | | 40 | } |