1*e6298b92Srillig /* $NetBSD: gcc_cast_union.c,v 1.4 2023/07/07 19:45:22 rillig Exp $ */
2a88eea7dSrillig # 3 "gcc_cast_union.c"
3a88eea7dSrillig
4a88eea7dSrillig /*
5a88eea7dSrillig * Test the GCC extension for casting to a union type.
6a88eea7dSrillig *
7a88eea7dSrillig * As of GCC 10.3.0, GCC only prints a generic warning without any details:
8a88eea7dSrillig * error: cast to union type from type not present in union
9a88eea7dSrillig * No idea why it neither mentions the union type nor the actual type.
10a88eea7dSrillig *
11a88eea7dSrillig * https://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html
12a88eea7dSrillig */
13a88eea7dSrillig
14*e6298b92Srillig /* lint1-extra-flags: -e -X 351 */
15d1299c8cSrillig
16a88eea7dSrillig union anything {
17a88eea7dSrillig _Bool m_bool;
18a88eea7dSrillig char m_char;
19a88eea7dSrillig signed char m_signed_char;
20a88eea7dSrillig unsigned char m_unsigned_char;
21a88eea7dSrillig short m_short;
22a88eea7dSrillig unsigned short m_unsigned_short;
23a88eea7dSrillig int m_int;
24a88eea7dSrillig unsigned int m_unsigned_int;
25a88eea7dSrillig long m_long;
26a88eea7dSrillig unsigned long m_unsigned_long;
27a88eea7dSrillig long long m_long_long;
28a88eea7dSrillig unsigned long long m_unsigned_long_long;
29a88eea7dSrillig /* skip __int128_t and __uint128_t for now */
30a88eea7dSrillig float m_float;
31a88eea7dSrillig double m_double;
32a88eea7dSrillig long double m_long_double;
33a88eea7dSrillig
34a88eea7dSrillig struct m_struct {
35a88eea7dSrillig int member;
36a88eea7dSrillig } m_struct;
37a88eea7dSrillig union m_union {
38a88eea7dSrillig int member;
39a88eea7dSrillig } m_union;
40a88eea7dSrillig enum m_enum1 {
41a88eea7dSrillig E1
42a88eea7dSrillig } m_enum1;
43a88eea7dSrillig enum m_enum2 {
44a88eea7dSrillig E2
45a88eea7dSrillig } m_enum2;
46a88eea7dSrillig const char *m_const_char_pointer;
47a88eea7dSrillig double m_double_array[5];
48a88eea7dSrillig void (*m_function)(void *);
49a88eea7dSrillig void (*m_function_varargs)(void *, ...);
50a88eea7dSrillig float _Complex m_float_complex;
51a88eea7dSrillig double _Complex m_double_complex;
52a88eea7dSrillig long double _Complex m_long_double_complex;
53a88eea7dSrillig };
54a88eea7dSrillig
55a88eea7dSrillig enum other_enum {
56a88eea7dSrillig OTHER
57a88eea7dSrillig };
58a88eea7dSrillig
59a88eea7dSrillig void
test(void)60a88eea7dSrillig test(void)
61a88eea7dSrillig {
62a88eea7dSrillig union anything any;
63a88eea7dSrillig
64a88eea7dSrillig any = (union anything)(_Bool)0;
65a88eea7dSrillig any = (union anything)(char)'\0';
66a88eea7dSrillig any = (union anything)(signed char)'\0';
67a88eea7dSrillig any = (union anything)(unsigned char)'\0';
68a88eea7dSrillig any = (union anything)(short)'\0';
69a88eea7dSrillig any = (union anything)(unsigned short)'\0';
70a88eea7dSrillig any = (union anything)(int)'\0';
71a88eea7dSrillig any = (union anything)(unsigned int)'\0';
72a88eea7dSrillig any = (union anything)(long)'\0';
73a88eea7dSrillig any = (union anything)(unsigned long)'\0';
74a88eea7dSrillig any = (union anything)(long long)'\0';
75a88eea7dSrillig any = (union anything)(unsigned long long)'\0';
76a88eea7dSrillig any = (union anything)0.0F;
77a88eea7dSrillig any = (union anything)0.0;
78a88eea7dSrillig any = (union anything)0.0L;
79a88eea7dSrillig any = (union anything)(struct m_struct){ 0 };
80a88eea7dSrillig any = (union anything)(union m_union){ 0 };
81a88eea7dSrillig any = (union anything)E1;
82a88eea7dSrillig any = (union anything)E2;
83a88eea7dSrillig /* GCC allows enum mismatch even with -Wenum-conversion */
843c10f944Srillig /* expect+1: error: type 'enum other_enum' is not a member of 'union anything' [329] */
85a88eea7dSrillig any = (union anything)OTHER;
86d1299c8cSrillig /* expect+1: error: type 'pointer to char' is not a member of 'union anything' [329] */
87a88eea7dSrillig any = (union anything)"char *";
88a88eea7dSrillig any = (union anything)(const char *)"char *";
89a88eea7dSrillig /* expect+1: error: type 'pointer to double' is not a member of 'union anything' [329] */
90a88eea7dSrillig any = (union anything)(double[5]){ 0.0, 1.0, 2.0, 3.0, 4.0 };
91a88eea7dSrillig /* expect+1: error: type 'pointer to double' is not a member of 'union anything' [329] */
92a88eea7dSrillig any = (union anything)(double[4]){ 0.0, 1.0, 2.0, 3.0 };
93a88eea7dSrillig /* expect+1: error: type 'pointer to int' is not a member of 'union anything' [329] */
94a88eea7dSrillig any = (union anything)(int[5]){ 0, 1, 2, 3, 4 };
95a88eea7dSrillig any = (union anything)(float _Complex)0.0F;
96a88eea7dSrillig any = (union anything)(double _Complex)0.0;
97a88eea7dSrillig any = (union anything)(long double _Complex)0.0L;
98a88eea7dSrillig
99a88eea7dSrillig any = any;
100a88eea7dSrillig }
101