1stdint.h(3HEAD) Headers stdint.h(3HEAD)
2
6 stdint.h, stdint - integer types
7
9 #include <stdint.h>
10
13 The <stdint.h> header declares sets of integer types having specified
14 widths, and defines corresponding sets of macros. It also defines
15 macros that specify limits of integer types corresponding to types
16 defined in other standard headers.
17 The ``width'' of an integer type is the number of bits used to store
20 its value in a pure binary system; the actual type can use more bits
21 than that (for example, a 28-bit type could be stored in 32 bits of
22 actual storage). An N-bit signed type has values in the range -2^N-1 or
23 1-2^N-1 to 2^N-1-1, while an N-bit unsigned type has values in the
24 range 0 to 2^N-1.
25 Types are defined in the following categories:
28 o integer types having certain exact widths
30 o integer types having at least certain specified widths
32 o fastest integer types having at least certain specified
34 widths
35 o integer types wide enough to hold pointers to objects
37 o integer types having greatest width
39 Some of these types may denote the same type.
42 Corresponding macros specify limits of the declared types and construct
45 suitable constants.
46 For each type described herein that the implementation provides, the
49 <stdint.h> header declares that typedef name and defines the associated
50 macros. Conversely, for each type described herein that the implementa‐
51 tion does not provide, the <stdint.h> header does not declare that
52 typedef name, nor does it define the associated macros. An implementa‐
53 tion provides those types described as required, but need not provide
54 any of the others (described as optional).
55 Integer Types
57 When typedef names differing only in the absence or presence of the
58 initial u are defined, they denote corresponding signed and unsigned
59 types as described in the ISO/IEC 9899: 1999 standard, Section 6.2.5;
60 an implementation providing one of these corresponding types must also
61 provide the other.
62 In the following descriptions, the symbol N represents an unsigned dec‐
65 imal integer with no leading zeros (for example, 8 or 24, but not 04 or
66 048).
67 Exact-width integer types
69 The typedef name intN_t designates a signed integer type with width
71 N, no padding bits, and a two's-complement representation. Thus,
72 int8_t denotes a signed integer type with a width of exactly 8
73 bits.
74 The typedef name uintN_t designates an unsigned integer type with
76 width N. Thus, uint24_t denotes an unsigned integer type with a
77 width of exactly 24 bits.
78 The following types are required:
80 int8_t
82 int16_t
83 int32_t
84 uint8_t
85 uint16_t
86 uint32_t
87 If an implementation provides integer types with width 64 that meet
89 these requirements, then the following types are required:
90 int64_t
92 uint64_t
93 In particular, this is the case if any of the following are true:
95 o The implementation supports the _POSIX_V6_ILP32_OFFBIG
97 programming environment and the application is being
98 built in the _POSI X_V6_ILP32_OFFBIG programming envi‐
99 ronment (see the Shell and Utilities volume of IEEE Std
100 1003.1-200x, c99, Programming Environments).
101 o The implementation supports the _POSIX_V6_LP64_OFF64
103 programming environment and the application is being
104 built in the _POSIX_ V6_LP64_OFF64 programming environ‐
105 ment.
106 o The implementation supports the _POSIX_V6_LPBIG_OFFBIG
108 programming environment and the application is being
109 built in the _POSIX_V6_LPBIG_OFFBIG programming environ‐
110 ment.
111 All other types of this form are optional.
112 Minimum-width integer types
115 The typedef name int_leastN_t designates a signed integer type with
117 a width of at least N, such that no signed integer type with lesser
118 size has at least the specified width. Thus, int_least32 _t denotes
119 a signed integer type with a width of at least 32 bits.
120 The typedef name uint_leastN_t designates an unsigned integer type
122 with a width of at least N, such that no unsigned integer type with
123 lesser size has at least the specified width. Thus, uint_ least16_t
124 denotes an unsigned integer type with a width of at least 16 bits.
125 The following types are required:
127 int_least8_t
129 int_least16_t
130 int_least32_t
131 int_least64_t
132 uint_least8_t
133 uint_least16_t
134 uint_least32_t
135 uint_least64_t
136 All other types of this form are optional.
138 Fastest minimum-width integer types
141 Each of the following types designates an integer type that is usu‐
143 ally fastest to operate with among all integer types that have at
144 least the specified width.
145 The designated type is not guaranteed to be fastest for all pur‐
147 poses; if the implementation has no clear grounds for choosing one
148 type over another, it will simply pick some integer type satisfying
149 the signedness and width requirements.
150 The typedef name int_fastN_t designates the fastest signed integer
152 type with a width of at least N. The typedef name uint_fastN_ t
153 designates the fastest unsigned integer type with a width of at
154 least N.
155 The following types are required:
157 int_fast8_t
159 int_fast16_t
160 int_fast32_t
161 int_fast64_t
162 uint_fast8_t
163 uint_fast16_t
164 uint_fast32_t
165 uint_fast64_t
166 All other types of this form are optional.
168 Integer types capable of holding object pointers
171 intptr_t Designates a signed integer type with the property
174 that any valid pointer to void can be converted to
175 this type, then converted back to a pointer to void,
176 and the result will compare equal to the original
177 pointer.
178 uintptr_t Designates an unsigned integer type with the property
181 that any valid pointer to void can be converted to
182 this type, then converted back to a pointer to void,
183 and the result will compare equal to the original
184 pointer.
185 On standard-conforming systems, the intptr_t and uintptr_t types
187 are required; otherwise, they are optional.
188 Greatest-width integer types
191 intmax_t Designates a signed integer type capable of represent‐
194 ing any value of any signed integer type.
195 uintmax_t Designates an unsigned integer type capable of repre‐
198 senting any value of any unsigned integer type.
199 These types are required.
201 Applications can test for optional types by using the corresponding
203 limit macro from Limits of Specified-Width Integer Types.
204 Limits of Specified-Width Integer Types
207 The following macros specify the minimum and maximum limits of the
208 types declared in the <stdint.h> header. Each macro name corresponds to
209 a similar type name in Integer Types.
210 Each instance of any defined macro is replaced by a constant expression
213 suitable for use in #if preprocessing directives. This expression has
214 the same type as would an expression that is an object of the corre‐
215 sponding type converted according to the integer promotions. Its imple‐
216 mentation-defined value is equal to or greater in magnitude (absolute
217 value) than the corresponding value given below, with the same sign,
218 except where stated to be exactly the given value.
219 Limits of exact-width integer types
221 o Minimum values of exact-width signed integer types:
224 {INTN_MIN} Exactly -(2^N-1)
227 o Maximum values of exact-width signed integer types:
231 {INTN_MAX} Exactly 2^N-1 -1
234 o Maximum values of exact-width unsigned integer types:
238 {UINTN_MAX} Exactly 2^N -1
241 Limits of minimum-width integer types
246 o Minimum values of minimum-width signed integer types:
249 {INT_LEASTN_MIN} -(2^N-1 -1)
252 o Maximum values of minimum-width signed integer types:
256 {INT_LEASTN_MAX} 2^N-1 -1
259 o Maximum values of minimum-width unsigned integer types:
263 {UINT_LEASTN_MAX} 2^N -1
266 Limits of fastest minimum-width integer types
271 o Minimum values of fastest minimum-width signed integer
274 types:
275 {INT_FASTN_MIN} -(2^N-1 -1)
278 o Maximum values of fastest minimum-width signed integer
282 types:
283 {INT_FASTN_MAX} 2^N-1 -1
286 o Maximum values of fastest minimum-width unsigned integer
290 types:
291 {UINT_FASTN_MAX} 2^N-1 -1
294 Limits of integer types capable of holding object pointers
299 o Minimum value of pointer-holding signed integer type:
302 {INTPTR_MIN} -(2^15 -1)
305 o Maximum value of pointer-holding signed integer type:
309 {INTPTR_MAX} 2^15 -1
312 o Minimum value of pointer-holding signed integer type:
316 {UINTPTR_MAX} 2^16 -1
319 Limits of greatest-width integer types
324 o Minimum value of greatest-width signed integer type:
327 {INTMAX_MIN} -(2^63 -1)
330 o Maximum value of greatest-width signed integer type:
334 {INTMAX_MIN} 2^63 -1
337 o Maximum value of greatest-width unsigned integer type:
341 {UINTMAX_MIN} 2^64 -1
344 Limits of Other Integer Types
352 The following macros specify the minimum and maximum limits of integer
353 types corresponding to types defined in other standard headers.
354 Each instance of these macros is replaced by a constant expression
357 suitable for use in #if preprocessing directives. This expression has
358 the same type as would an expression that is an object of the corre‐
359 sponding type converted according to the integer promotions. Its imple‐
360 mentation-defined value is equal to or greater in magnitude (absolute
361 value) than the corresponding value given below, with the same sign.
362 Limits of ptrdiff_t:
364 {PTRDIFF_MIN} -65535
365 {PTRDIFF_MAX} +65535
368 Limits of sig_atomic_t:
372 {SIG_ATOMIC_MIN} See below.
373 {SIG_ATOMIC_MAX} See below.
376 Limits of size_t:
380 {SIZE_MAX} 65535
381 Limits of wchar_t:
385 {WCHAR_MIN} See below.
386 {WCHAR_MAX} See below.
389 Limits of wint_t:
393 {WINT_MIN} See below.
394 {WINT_MAX} See below.
397 If sig_atomic_t (see the <signal.h> header) is defined as a signed
402 integer type, the value of {SIG_ATOMIC_MIN} is no greater than -127 and
403 the value of {SIG_ATOMIC_MAX} is no less than 127. Otherwise,
404 sig_atomic_t is defined as an unsigned integer type, the value of
405 {SIG_ATOMIC_MIN} is 0, and the value of {SIG_ATOMIC_MAX} is no less
406 than 255.
407 If wchar_t (see the <stddef.h> header) is defined as a signed integer
410 type, the value of {WCHAR_MIN} is no greater than -127 and the value
411 of {WCHAR_MAX} is no less than 127. Otherwise, wchar_t is defined as an
412 unsigned integer type, and the value of {WCHAR_MIN} is 0 and the value
413 of {WCHAR_MAX} is no less than 255.
414 If wint_t (see the <wchar.h> header) is defined as a signed integer
417 type, the value of {WINT_MIN} is no greater than -32767 and the value
418 of {WINT_MAX} is no less than 32767. Otherwise, wint_t is defined as an
419 unsigned integer type, and the value of {WINT_MIN} is 0 and the value
420 of {WINT_MAX} is no less than 65535.
421 Macros for Integer Constant Expressions
423 The following macros expand to integer constant expressions suitable
424 for initializing objects that have integer types corresponding to types
425 defined in the <stdint.h> header. Each macro name corresponds to a sim‐
426 ilar type name listed under minimum-width integer types and greatest-
427 width integer types.
428 Each invocation of one of these macros expands to an integer constant
431 expression suitable for use in #if preprocessing directives. The type
432 of the expression has the same type as would an expression that is an
433 object of the corresponding type converted according to the integer
434 promotions. The value of the expression is that of the argument. The
435 argument in any instance of these macros is a decimal, octal, or hexa‐
436 decimal constant with a value that does not exceed the limits for the
437 corresponding type.
438 Macros for minimum-width integer constant expressions
440 The macro INTN_C(value) expands to an integer constant expression
442 corresponding to the type int_leastN_t. The macro UINTN_C(value)
443 expands to an integer constant expression corresponding to the type
444 uint_leastN_t. For example, if uint_least64_t is a name for the
445 type unsigned long long, then UINT64_C(0x123) might expand to the
446 integer constant 0x123ULL.
447 Macros for greatest-width integer constant expressions
450 The following macro expands to an integer constant expression hav‐
452 ing the value specified by its argument and the type intmax_t:
453 INTMAX_C(value)
455 The following macro expands to an integer constant expression hav‐
457 ing the value specified by its argument and the type uintmax_t:
458 UINTMAX_C(value)
460
464 See attributes(5) for descriptions of the following attributes:
465 ┌─────────────────────────────┬─────────────────────────────┐
470 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
471 ├─────────────────────────────┼─────────────────────────────┤
472 │Interface Stability │Standard │
473 └─────────────────────────────┴─────────────────────────────┘
474
476 inttypes.h(3HEAD), signal.h(3HEAD), stddef.h(3HEAD), wchar.h(3HEAD),
477 attributes(5), standards(5)
478SunOS 5.11 10 Sep 2004 stdint.h(3HEAD)