sdcc/support/regression/tests/const.c

   1 /* Tests usage of const qualifier.
   2  */
   3 #include <testfwk.h>
   4
   5 char k;                                 /* char */
   6 const char const_char = 123;            /* constant char */
   7 const char * const_char_ptr;            /* pointer to constant char */
   8 char * const char_ptr_const = &k;       /* constant pointer to char */
   9 const char * const const_char_ptr_const = &const_char;
  10                                         /* constant pointer to constant char */
  11 char char_array[3];                     /* array of char */
  12 const char const_char_array[] = {1,2,3}; /* array of constant char */
  13 const char ** const_char_ptr_ptr;       /* pointer to pointer to constant char */
  14
  15 char
  16 ident(char x)
  17 {
  18   return x;
  19 }
  20
  21 void
  22 testConst(void)
  23 {
  24   /* Since const_char_ptr is in itself not constant, we can change it */
  25   const_char_ptr = const_char_array;
  26   const_char_ptr++;
  27   ASSERT(*const_char_ptr == 2);
  28
  29   /* Check for bug #621531 */
  30   const_char_ptr = const_char_array;
  31   ASSERT(const_char_ptr[0] == 1);
  32   const_char_ptr++;
  33
  34   /* Since char_ptr_const is constant, we cannot change it. However, */
  35   /* we can change the object that it points to.                     */
  36   *char_ptr_const = 5;
  37   ASSERT(ident(*char_ptr_const)==5);
  38   (*char_ptr_const)++;
  39   ASSERT(ident(*char_ptr_const)==6);
  40
  41   /* We can't modify const_char_ptr_const or the object that it points */
  42   /* to. Unfortunately, we can't test that compiler enforces these     */
  43   /* restriction, so just verify its initialization.                   */
  44   ASSERT(*const_char_ptr_const == const_char);
  45
  46   /* We can change const_char_ptr_ptr or the object that it points to. */
  47   const_char_ptr = const_char_array;
  48   const_char_ptr_ptr = &const_char_ptr;
  49   ASSERT(ident(**const_char_ptr_ptr)==1);
  50   (*const_char_ptr_ptr)++;
  51   ASSERT(ident(**const_char_ptr_ptr)==2);
  52 }