gcc/testsuite/gcc.dg/gnu99-static-1.c

   1 /* It is a constraint violation for a static function to be declared
   2    but not defined if it is used except in a sizeof expression whose
   3    result is an integer constant.  In GNU C, we need to consider
   4    __typeof__ and __alignof__ as well.  __alignof__ always returns a
   5    constant, so static functions can always be used therein.
   6    __typeof__ evaluates its argument iff it has variably modified
   7    type.  */
   8 /* Origin: Joseph Myers <jsm@polyomino.org.uk> */
   9 /* { dg-do compile } */
  10 /* { dg-options "-O2 -std=gnu99 -pedantic-errors" } */
  11
  12 /* __alignof__, OK.  */
  13 static int f0(void);
  14 void g0(void) { __alignof__(f0()); }
  15
  16 /* __typeof__ not variably modified, OK.  */
  17 static int f1(void);
  18 void g1(void) { __typeof__(f1()) x; }
  19
  20 /* __typeof__ variably modified, not OK.  */
  21 static int f2(void); /* { dg-error "used but never defined" } */
  22 void g2(void) { __typeof__(int [f2()]) x; }
  23
  24 /* __typeof__ variably modified, not OK.  */
  25 static int f3(void); /* { dg-error "used but never defined" } */
  26 void g3(void) { __typeof__(int (*)[f3()]) x; }
  27
  28 /* Integer sizeof of VM typeof, OK.  */
  29 static int f4(void);
  30 void g4(void) { sizeof(__typeof__(int (*)[f3()])); }