gcc/testsuite/gcc.dg/pr30457.c

   1 /* PR 30457 warn about va_start(ap, invalid) */
   2 /* { dg-do compile } */
   3 /* { dg-options "-std=c99" } */
   4
   5 /* Undefined by C99 7.15.1.4p4 (va_start):
   6    "If the parameter parmN is declared with the register storage
   7     class, with a function or array type, or with a type that is
   8     not compatible with the type that results after application of
   9     the default argument promotions, the behavior is undefined."  */
  10
  11 #include <stdarg.h>
  12
  13 void foo(register short paramN, ...)
  14 {
  15   va_list ap;
  16
  17   va_start(ap, paramN); /* { dg-warning "undefined behaviour when second parameter of 'va_start' is declared with 'register' storage" } */
  18
  19   /* Undefined by C99 7.15.1.1p2:  */
  20   (void) va_arg(ap, char); /* { dg-warning "'char' is promoted to 'int' when passed through '...'" } */
  21   /* { dg-message "note: .so you should pass .int. not .char. to .va_arg.." "" { target *-*-* } 20 } */
  22   /* { dg-message "note: if this code is reached, the program will abort"  "" { target *-*-* } 20 } */
  23
  24   va_end(ap);
  25 }
  26