gcc/testsuite/gcc.dg/c23-attr-noreturn-1.c

   1 /* Test C23 noreturn attribute: valid uses.  */
   2 /* { dg-do compile } */
   3 /* { dg-options "-std=c23 -pedantic-errors" } */
   4
   5 [[noreturn]] void exit (int);
   6
   7 [[__noreturn__]] int f1 (void);
   8
   9 [[_Noreturn]] void f2 (void);
  10
  11 [[___Noreturn__]] static void f3 (void) { exit (0); }
  12
  13 /* Returning from a noreturn function is undefined at runtime, not a
  14    constraint violation, but recommended practice is to diagnose if
  15    such a return appears possible.  */
  16
  17 [[noreturn]] int
  18 f4 (void)
  19 {
  20   return 1; /* { dg-warning "has a 'return' statement" } */
  21   /* { dg-warning "does return" "second warning" { target *-*-* } .-1 } */
  22 }
  23
  24 [[__noreturn__]] void
  25 f5 (void)
  26 {
  27   return; /* { dg-warning "has a 'return' statement" } */
  28   /* { dg-warning "does return" "second warning" { target *-*-* } .-1 } */
  29 }
  30
  31 [[_Noreturn]] void
  32 f6 (void)
  33 {
  34 } /* { dg-warning "does return" } */
  35
  36 [[___Noreturn__]] void
  37 f7 (int a)
  38 {
  39   if (a)
  40     exit (0);
  41 } /* { dg-warning "does return" } */
  42
  43 /* Declarations need not all have the attribute (buf if the first does not,
  44    there is undefined behavior).  */
  45
  46 void f2 (void);
  47
  48 /* Duplicate attribute, and use with _Noreturn, is OK.  */
  49 [[noreturn]] [[noreturn]] [[noreturn, __noreturn__]] void _Noreturn f9 (void);
  50
  51 /* The attribute does not affect type compatibility.  */
  52
  53 void (*fp) (void) = f5;
  54
  55 /* Unlike the function specifier, the attribute may be used on main.  */
  56 [[noreturn]] int main ();