validation/enum-sign-gcc.c

   1 // For enum's underlying/compatible type:
   2 //  std C:      unspecified
   3 //  GCC:        'unsigned int' if no negative values,
   4 //              otherwise 'int' (see GCC manul 4.9).
   5 //              But also accept ulong, long
   6 // For the type of the enumerators:
   7 // std C:       'int'
   8 // GCC:         'int' if the value fit in a 'int'
   9 //              otherwise same as the enum underlying type?
  10 //
  11 // The following tests match GCC's choices
  12
  13 #define is_unsigned(X) ((typeof(X))-1 > 0)
  14
  15 enum u {
  16         U = 1U,                 // fit in 'int'
  17         // no negatives
  18 };
  19 _Static_assert(sizeof(enum u) == sizeof(int), "size");
  20 _Static_assert(is_unsigned(enum u), "enum u");
  21 _Static_assert(is_unsigned(U) == 0, "value U");         // fail
  22
  23 enum v {
  24         V = __INT_MAX__ + 1U,   // doesn't fit in 'int'
  25         // no negatives
  26 };
  27 _Static_assert(sizeof(enum v) == sizeof(int), "size");
  28 _Static_assert(is_unsigned(enum v), "enum v");
  29 _Static_assert(is_unsigned(V) == 1, "value V");
  30
  31 enum w {
  32         W = __LONG_MAX__ + 1UL, // doesn't fit in 'long'
  33 };
  34 _Static_assert(sizeof(enum w) == sizeof(long), "size");
  35 _Static_assert(is_unsigned(enum w), "enum w");
  36 _Static_assert(is_unsigned(W) == 1, "value W");
  37
  38 enum x {
  39         A = 1,                  // fit in 'int'
  40         B = 0x100000000UL,      // doesn't fit in int
  41 };
  42 _Static_assert(sizeof(enum x) == sizeof(long), "size");
  43 _Static_assert(is_unsigned(enum x), "enum x");
  44 _Static_assert(sizeof(A) == sizeof(int), "size A");     // fail
  45 _Static_assert(is_unsigned(A) == 0, "enum A");          // fail
  46 _Static_assert(sizeof(B) == sizeof(long), "size B");
  47 _Static_assert(is_unsigned(B) == 1, "enum B");
  48
  49 enum y {
  50         C = 1,                  // fit in 'int'
  51         D = 0x100000000L,       // doesn't fit in int
  52 };
  53 _Static_assert(sizeof(enum y) == sizeof(long), "size");
  54 _Static_assert(is_unsigned(enum y), "enum y");
  55 _Static_assert(sizeof(C) == sizeof(int), "size C");     // fail
  56 _Static_assert(is_unsigned(C) == 0, "enum C");          // fail
  57 _Static_assert(sizeof(D) == sizeof(long), "size D");
  58 _Static_assert(is_unsigned(D) == 1, "enum D");
  59
  60 /*
  61  * check-name: enum-sign-gcc
  62  * check-command: sparse -m64 $file
  63  * check-assert: sizeof(long) == 8
  64  */