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
15enum 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
23enum 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
31enum 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
38enum 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
49enum 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 */
65