1 /* $NetBSD: msg_217.c,v 1.16 2024/11/30 11:27:20 rillig Exp $ */ 2 # 3 "msg_217.c" 3 4 // Test for message: function '%s' falls off bottom without returning value [217] 5 6 /* lint1-extra-flags: -X 351 */ 7 8 int 9 random(int n) 10 { 11 if (n < 0) 12 return -3; 13 } 14 /* expect-1: warning: function 'random' falls off bottom without returning value [217] */ 15 16 /* 17 * The pattern 'do { } while (0)' is often used in statement macros. 18 * Putting a 'return' at the end of such a macro is legitimate, the embracing 19 * 'do { } while (0)' is probably there to conform to a coding standard or 20 * to otherwise reduce confusion. 21 * 22 * Seen in external/bsd/libevent/dist/event_tagging.c, function 23 * encode_int_internal. 24 * 25 * Before tree.c 1.243 from 2021-03-21, lint wrongly reported that the 26 * 'while 0' was unreachable. This has been fixed by allowing the 'while 0' 27 * in a do-while-false loop to be unreachable. The same could be useful for a 28 * do-while-true. 29 * 30 * Before func.c 1.83 from 2021-03-21, lint wrongly reported that the function 31 * would fall off the bottom. 32 */ 33 int 34 do_while_return(int i) 35 { 36 do { 37 return i; 38 } while (0); 39 } 40 41 /* 42 * C99 5.1.2.2.3 "Program termination" p1 defines that as a special exception, 43 * the function 'main' does not have to return a value, reaching the bottom 44 * is equivalent to returning 0. 45 * 46 * Before func.c 1.72 from 2021-02-21, lint had wrongly warned about this. 47 */ 48 int 49 main(void) 50 { 51 } 52 53 int 54 reachable_continue_leads_to_endless_loop(void) 55 { 56 for (;;) { 57 if (1) 58 continue; 59 break; 60 } 61 } 62 63 int 64 unreachable_continue_falls_through(void) 65 { 66 for (;;) { 67 if (0) 68 /* expect+1: warning: 'continue' statement not reached [193] */ 69 continue; 70 break; 71 } 72 } 73 /* expect-1: warning: function 'unreachable_continue_falls_through' falls off bottom without returning value [217] */ 74 75 76 _Noreturn void noreturn_c11(void); 77 [[noreturn]] void noreturn_c23(void); 78 __attribute__((__noreturn__)) void noreturn_gnu_prefix(void); 79 void __attribute__((__noreturn__)) noreturn_gnu_infix(void); 80 void noreturn_gnu_suffix(void) __attribute__((__noreturn__)); 81 82 int 83 call_noreturn_c11(void) 84 { 85 noreturn_c11(); 86 } 87 88 inline int 89 call_noreturn_c23(void) 90 { 91 noreturn_c23(); 92 } 93 94 int 95 call_noreturn_gnu_prefix(void) 96 { 97 noreturn_gnu_prefix(); 98 } 99 100 int 101 call_noreturn_gnu_infix(void) 102 { 103 noreturn_gnu_infix(); 104 } 105 106 int 107 call_noreturn_gnu_suffix(void) 108 { 109 noreturn_gnu_suffix(); 110 } 111 112 113 double *force_function_attributes_in_diagnostic[] = { 114 // Force the word 'noreturn' to occur in a diagnostic. 115 /* expect+1: warning: illegal combination of 'pointer to double' and 'pointer to noreturn function(void) returning void', op 'init' [124] */ 116 noreturn_c23, 117 // The 'inline' does affect the type of the function. 118 /* expect+1: warning: illegal combination of 'pointer to double' and 'pointer to function(void) returning int', op 'init' [124] */ 119 call_noreturn_c23, 120 }; 121