101 lines
2.9 KiB
C
101 lines
2.9 KiB
C
/* $NetBSD: gcc_cast_union.c,v 1.4 2023/07/07 19:45:22 rillig Exp $ */
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# 3 "gcc_cast_union.c"
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/*
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* Test the GCC extension for casting to a union type.
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*
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* As of GCC 10.3.0, GCC only prints a generic warning without any details:
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* error: cast to union type from type not present in union
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* No idea why it neither mentions the union type nor the actual type.
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*
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* https://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html
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*/
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/* lint1-extra-flags: -e -X 351 */
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union anything {
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_Bool m_bool;
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char m_char;
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signed char m_signed_char;
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unsigned char m_unsigned_char;
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short m_short;
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unsigned short m_unsigned_short;
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int m_int;
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unsigned int m_unsigned_int;
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long m_long;
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unsigned long m_unsigned_long;
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long long m_long_long;
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unsigned long long m_unsigned_long_long;
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/* skip __int128_t and __uint128_t for now */
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float m_float;
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double m_double;
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long double m_long_double;
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struct m_struct {
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int member;
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} m_struct;
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union m_union {
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int member;
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} m_union;
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enum m_enum1 {
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E1
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} m_enum1;
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enum m_enum2 {
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E2
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} m_enum2;
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const char *m_const_char_pointer;
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double m_double_array[5];
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void (*m_function)(void *);
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void (*m_function_varargs)(void *, ...);
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float _Complex m_float_complex;
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double _Complex m_double_complex;
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long double _Complex m_long_double_complex;
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};
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enum other_enum {
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OTHER
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};
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void
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test(void)
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{
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union anything any;
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any = (union anything)(_Bool)0;
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any = (union anything)(char)'\0';
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any = (union anything)(signed char)'\0';
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any = (union anything)(unsigned char)'\0';
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any = (union anything)(short)'\0';
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any = (union anything)(unsigned short)'\0';
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any = (union anything)(int)'\0';
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any = (union anything)(unsigned int)'\0';
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any = (union anything)(long)'\0';
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any = (union anything)(unsigned long)'\0';
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any = (union anything)(long long)'\0';
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any = (union anything)(unsigned long long)'\0';
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any = (union anything)0.0F;
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any = (union anything)0.0;
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any = (union anything)0.0L;
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any = (union anything)(struct m_struct){ 0 };
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any = (union anything)(union m_union){ 0 };
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any = (union anything)E1;
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any = (union anything)E2;
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/* GCC allows enum mismatch even with -Wenum-conversion */
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/* expect+1: error: type 'enum other_enum' is not a member of 'union anything' [329] */
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any = (union anything)OTHER;
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/* expect+1: error: type 'pointer to char' is not a member of 'union anything' [329] */
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any = (union anything)"char *";
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any = (union anything)(const char *)"char *";
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/* expect+1: error: type 'pointer to double' is not a member of 'union anything' [329] */
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any = (union anything)(double[5]){ 0.0, 1.0, 2.0, 3.0, 4.0 };
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/* expect+1: error: type 'pointer to double' is not a member of 'union anything' [329] */
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any = (union anything)(double[4]){ 0.0, 1.0, 2.0, 3.0 };
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/* expect+1: error: type 'pointer to int' is not a member of 'union anything' [329] */
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any = (union anything)(int[5]){ 0, 1, 2, 3, 4 };
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any = (union anything)(float _Complex)0.0F;
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any = (union anything)(double _Complex)0.0;
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any = (union anything)(long double _Complex)0.0L;
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any = any;
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}
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