1 [section:cstdint Standard Integer Types]
5 The header [^[@../../../../boost/cstdint.hpp <boost/cstdint.hpp>]] provides the typedef's useful
6 for writing portable code that requires certain integer widths. All typedef's are in namespace boost.
8 The specifications for these types are based on the ISO/IEC 9899:1999 C Language standard header <stdint.h>.
9 The 64-bit types required by the C standard are ['not required] in the boost header,
10 and may not be supplied for all platforms/compilers, because [^long long] is not [yet] included in the C++ standard.
12 See [@../../test/cstdint_test.cpp cstdint_test.cpp] for a test program.
16 [section:rationale Rationale]
18 The organization of the Boost.Integer headers and classes is designed to take advantage of <stdint.h> types from the
19 1999 C standard without causing undefined behavior in terms of the 1998 C++ standard.
20 The header <boost/cstdint.hpp> makes the standard integer types safely available in namespace [^boost]
21 without placing any names in namespace [^std]. The intension is to complement rather than compete
22 with the C++ Standard Library. Should some future C++ standard include <stdint.h> and <cstdint>,
23 then <boost/cstdint.hpp> will continue to function, but will become redundant and may be safely deprecated.
25 Because these are boost headers, their names conform to boost header naming conventions rather than
26 C++ Standard Library header naming conventions.
30 [section:ce ['Caveat emptor]]
32 As an implementation artifact, certain C <limits.h> macro names may possibly be
33 visible to users of <boost/cstdint.hpp>. Don't use these macros; they are not part of
34 any Boost-specified interface. Use [^boost::integer_traits<>] or [^std::numeric_limits<>] instead.
36 As another implementation artifact, certain C <stdint.h> typedef names may possibly be visible
37 in the global namespace to users of <boost/cstdint.hpp>. Don't use these names, they are not part of
38 any Boost-specified interface. Use the respective names in namespace [^boost] instead.
42 [section Exact-width integer types]
44 The typedef [^int#_t], with # replaced by the width, designates a signed integer type of exactly # bits;
45 for example [^int8_t] denotes an 8-bit signed integer type. Similarly, the typedef [^uint#_t] designates an unsigned
46 integer type of exactly # bits.
48 These types are optional. However, if a platform supports integer types with widths of
49 8, 16, 32, 64, or any combination thereof, then <boost/cstdint.hpp> does provide the
50 corresponding typedefs.
52 The absence of int64_t and uint64_t is indicated by the macro `BOOST_NO_INT64_T`.
56 [section Minimum-width integer types]
58 The typedef [^int_least#_t], with # replaced by the width, designates a signed integer type with a width
59 of at least # bits, such that no signed integer type with lesser size has at least the specified width.
60 Thus, [^int_least32_t] denotes the smallest signed integer type with a width of at least 32 bits.
61 Similarly, the typedef name [^uint_least#_t] designates an unsigned integer type with a width of at least # bits,
62 such that no unsigned integer type with lesser size has at least the specified width.
64 The following minimum-width integer types are provided for all platforms:
73 The following types are available only if, after including <boost/cstdint.hpp>, the macro BOOST_NO_INT64_T is not defined:
79 All other minimum-width integer types are optional.
83 [section Fastest minimum-width integer types]
85 The typedef [^int_fast#_t], with # replaced by the width, designates the fastest signed integer type
86 with a width of at least # bits. Similarly, the typedef name [^uint_fast#_t] designates the fastest
87 unsigned integer type with a width of at least # bits.
89 There is no guarantee that these types are fastest for all purposes. In any case, however, they satisfy
90 the signedness and width requirements.
92 The following fastest minimum-width integer types are provided for all platforms:
101 The following types are available only if, after including <boost/cstdint.hpp>, the macro BOOST_NO_INT64_T is not defined:
106 All other fastest minimum-width integer types are optional.
110 [section Greatest-width integer types]
112 The typedef [^intmax_t ]designates a signed integer type capable of representing any value of any signed integer type.
114 The typedef [^uintmax_t] designates an unsigned integer type capable of representing any value of any unsigned integer type.
116 These types are provided for all platforms.
120 [section Integer Constant Macros]
122 The following macros are always defined after inclusion of this header, these allow
123 integer constants of at least the specified width to be declared:
124 INT8_C, UINT8_C, INT16_C, UINT16_C, INT32_C, UINT32_C, INTMAX_C, UINTMAX_C.
126 The macros INT64_C and UINT64_C are also defined if the the macro BOOST_NO_INT64_T is not defined.
128 The C99 macro __STDC_CONSTANT_MACROS is also defined as an artifact of the implementation.
132 #include <boost/cstdint.hpp>
134 // Here the constant 0x1FFFFFFFF has the correct suffix applied:
135 static const boost::uint64_t c = INT64_C(0x1FFFFFFFF);