/* $NetBSD: d_c99_bool.c,v 1.9 2022/01/16 08:40:31 rillig Exp $ */ # 3 "d_c99_bool.c" /* * C99 6.3.1.2 says: "When any scalar value is converted to _Bool, the result * is 0 if the value compares equal to 0; otherwise the result is 1." * * This is different from the other integer types, which get truncated or * invoke undefined behavior. */ /* Below, each false statement produces "negative array dimension" [20]. */ int int_0_converts_to_false[(_Bool)0 ? -1 : 1]; /* expect+1: error: negative array dimension (-1) [20] */ int int_0_converts_to_true_[(_Bool)0 ? 1 : -1]; /* expect+1: error: negative array dimension (-1) [20] */ int int_1_converts_to_false[(_Bool)1 ? -1 : 1]; int int_1_converts_to_true_[(_Bool)1 ? 1 : -1]; /* expect+1: error: negative array dimension (-1) [20] */ int int_2_converts_to_false[(_Bool)2 ? -1 : 1]; int int_2_converts_to_true_[(_Bool)2 ? 1 : -1]; /* expect+1: error: negative array dimension (-1) [20] */ int int_256_converts_to_false[(_Bool)256 ? -1 : 1]; int int_256_converts_to_true_[(_Bool)256 ? 1 : -1]; int null_pointer_converts_to_false[(_Bool)(void *)0 ? -1 : 1]; /* expect+1: error: negative array dimension (-1) [20] */ int null_pointer_converts_to_true_[(_Bool)(void *)0 ? 1 : -1]; /* * XXX: lint does not treat the address of a global variable as a constant * expression. This goes against C99 6.6p7 but is probably not too relevant * in practice. * * In such a case, to_int_constant(tn, false) in cgram.y:array_size_opt * returns 1 for the array size. This is why neither of the following array * declarations generates an error message. */ char ch; int nonnull_pointer_converts_to_false[(_Bool)&ch ? -1 : 1]; int nonnull_pointer_converts_to_true_[(_Bool)&ch ? 1 : -1]; /* expect+1: error: negative array dimension (-1) [20] */ int double_minus_1_0_converts_to_false[(_Bool)-1.0 ? -1 : 1]; int double_minus_1_0_converts_to_true_[(_Bool)-1.0 ? 1 : -1]; /* expect+1: error: negative array dimension (-1) [20] */ int double_minus_0_5_converts_to_false[(_Bool)-0.5 ? -1 : 1]; int double_minus_0_5_converts_to_true_[(_Bool)-0.5 ? 1 : -1]; int double_minus_0_0_converts_to_false[(_Bool)-0.0 ? -1 : 1]; /* expect+1: error: negative array dimension (-1) [20] */ int double_minus_0_0_converts_to_true_[(_Bool)-0.0 ? 1 : -1]; int double_0_0_converts_to_false[(_Bool)0.0 ? -1 : 1]; /* expect+1: error: negative array dimension (-1) [20] */ int double_0_0_converts_to_true_[(_Bool)0.0 ? 1 : -1]; /* The C99 rationale explains in 6.3.1.2 why (_Bool)0.5 is true. */ /* expect+1: error: negative array dimension (-1) [20] */ int double_0_5_converts_to_false[(_Bool)0.5 ? -1 : 1]; int double_0_5_converts_to_true_[(_Bool)0.5 ? 1 : -1]; /* expect+1: error: negative array dimension (-1) [20] */ int double_1_0_converts_to_false[(_Bool)1.0 ? -1 : 1]; int double_1_0_converts_to_true_[(_Bool)1.0 ? 1 : -1]; _Bool bool_to_bool(_Bool b) { return b; } _Bool char_to_bool(char c) { return c; } _Bool int_to_bool(int i) { return i; } _Bool double_to_bool(double d) { return d; } enum color { RED }; _Bool enum_to_bool(enum color e) { return e; } _Bool pointer_to_bool(const char *p) { return p; } _Bool function_pointer_to_bool(void (*f)(void)) { return f; } _Bool complex_to_bool(double _Complex c) { return c; }