stdint.h(feed) - phpMan

<stdint.h>(0P)             POSIX Programmer's Manual            <stdint.h>(0P)

NAME
       stdint.h - integer types
SYNOPSIS
       #include <stdint.h>
DESCRIPTION
       Some  of the functionality described on this reference page extends the
       ISO C standard. Applications shall define the appropriate feature  test
       macro  (see  the System Interfaces volume of IEEE Std 1003.1-2001, Sec-
       tion 2.2, The Compilation Environment)  to  enable  the  visibility  of
       these symbols in this header.
       The <stdint.h> header shall declare sets of integer types having speci-
       fied widths, and shall define corresponding sets of  macros.  It  shall
       also  define  macros that specify limits of integer types corresponding
       to types defined in other standard headers.
       Note:  The "width" of an integer type is the number  of  bits  used  to
              store its value in a pure binary system; the actual type may use
              more bits than that (for example, a 28-bit type could be  stored
              in  32  bits of actual storage). An N-bit signed type has values
              in the range -2**N-1 or 1-2**N-1 to  2**N-1-1,  while  an  N-bit
              unsigned type has values in the range 0 to 2**N-1.

       Types are defined in the following categories:
        * Integer types having certain exact widths
        * Integer types having at least certain specified widths
        * Fastest integer types having at least certain specified widths
        * Integer types wide enough to hold pointers to objects
        * Integer types having greatest width
       (Some of these types may denote the same type.)
       Corresponding macros specify limits of the declared types and construct
       suitable constants.
       For each type described herein that the  implementation  provides,  the
       <stdint.h>  header shall declare that typedef name and define the asso-
       ciated macros. Conversely, for each  type  described  herein  that  the
       implementation  does  not  provide,  the  <stdint.h>  header  shall not
       declare that typedef name, nor shall it define the  associated  macros.
       An  implementation shall provide those types described as required, but
       need not provide any of the others (described as optional).
   Integer Types
       When typedef names differing only in the absence  or  presence  of  the
       initial  u  are  defined,  they  shall  denote corresponding signed and
       unsigned types as described in the ISO/IEC 9899:1999 standard,  Section
       6.2.5;  an  implementation  providing  one of these corresponding types
       shall also provide the other.
       In the following descriptions, the symbol N represents an unsigned dec-
       imal integer with no leading zeros (for example, 8 or 24, but not 04 or
       048).
        * Exact-width integer types
       The typedef name int N _t designates a signed integer type  with  width
       N, no padding bits, and a two's-complement representation. Thus, int8_t
       denotes a signed integer type with a width of exactly 8 bits.
       The typedef name uint N _t designates an  unsigned  integer  type  with
       width  N.  Thus, uint24_t denotes an unsigned integer type with a width
       of exactly 24 bits.
       The following types are required:
       int8_t
       int16_t
       int32_t
       uint8_t
       uint16_t
       uint32_t
       If an implementation provides integer types with  width  64  that  meet
       these  requirements,  then  the  following  types are required: int64_t
       uint64_t
       In particular, this will be the case if any of the following are true:
               * The implementation supports the  _POSIX_V6_ILP32_OFFBIG  pro-
                 gramming  environment  and  the application is being built in
                 the _POSIX_V6_ILP32_OFFBIG programming environment  (see  the
                 Shell and Utilities volume of IEEE Std 1003.1-2001, c99, Pro-
                 gramming Environments).
               * The implementation supports the _POSIX_V6_LP64_OFF64 program-
                 ming  environment  and  the application is being built in the
                 _POSIX_V6_LP64_OFF64 programming environment.
               * The implementation supports the  _POSIX_V6_LPBIG_OFFBIG  pro-
                 gramming  environment  and  the application is being built in
                 the _POSIX_V6_LPBIG_OFFBIG programming environment.
       All other types of this form are optional.
        * Minimum-width integer types
       The typedef name int_least N _t designates a signed integer type with a
       width  of at least N, such that no signed integer type with lesser size
       has at least the specified width. Thus, int_least32_t denotes a  signed
       integer type with a width of at least 32 bits.
       The  typedef  name  uint_least N _t designates an unsigned integer type
       with a width of at least N, such that no  unsigned  integer  type  with
       lesser  size  has  at  least  the specified width. Thus, uint_least16_t
       denotes an unsigned integer type with a width of at least 16 bits.
       The  following   types   are   required:   int_least8_t   int_least16_t
       int_least32_t int_least64_t uint_least8_t uint_least16_t uint_least32_t
       uint_least64_t
       All other types of this form are optional.
        * Fastest minimum-width integer types
       Each of the following types designates an integer type that is  usually
       fastest  to operate with among all integer types that have at least the
       specified width.
       The designated type is not guaranteed to be fastest for  all  purposes;
       if  the  implementation has no clear grounds for choosing one type over
       another, it will simply pick some integer type satisfying  the  signed-
       ness and width requirements.
       The  typedef  name  int_fast N _t designates the fastest signed integer
       type with a width of at least N. The typedef name uint_fast N _t desig-
       nates the fastest unsigned integer type with a width of at least N.
       The following types are required: int_fast8_t int_fast16_t int_fast32_t
       int_fast64_t uint_fast8_t uint_fast16_t uint_fast32_t uint_fast64_t
       All other types of this form are optional.
        * Integer types capable of holding object pointers
       The following type designates a signed integer type with  the  property
       that any valid pointer to void can be converted to this type, then con-
       verted back to a pointer to void, and the result will compare equal  to
       the original pointer: intptr_t
       The  following  type designates an unsigned integer type with the prop-
       erty that any valid pointer to void can be converted to this type, then
       converted  back to a pointer to void, and the result will compare equal
       to the original pointer: uintptr_t
       On  XSI-conformant  systems,  the  intptr_t  and  uintptr_t  types  are
       required; otherwise, they are optional.
        * Greatest-width integer types
       The  following  type designates a signed integer type capable of repre-
       senting any value of any signed integer type: intmax_t
       The following type designates an unsigned integer type capable of  rep-
       resenting any value of any unsigned integer type: uintmax_t
       These types are required.
       Note:  Applications  can  test  for  optional types by using the corre-
              sponding limit macro  from  Limits  of  Specified-Width  Integer
              Types .

   Limits of Specified-Width Integer Types
       The  following  macros  specify  the  minimum and maximum limits of the
       types declared in the <stdint.h> header. Each macro name corresponds to
       a similar type name in Integer Types .
       Each  instance  of  any  defined  macro shall be replaced by a constant
       expression suitable for use in #if preprocessing directives,  and  this
       expression  shall  have the same type as would an expression that is an
       object of the corresponding type converted  according  to  the  integer
       promotions.  Its  implementation-defined  value  shall  be  equal to or
       greater in magnitude (absolute  value)  than  the  corresponding  value
       given  below, with the same sign, except where stated to be exactly the
       given value.
        * Limits of exact-width integer types
           * Minimum values of exact-width signed integer types:
          {INTN_MIN}
                 Exactly -(2 **N-1)

           * Maximum values of exact-width signed integer types:
          {INTN_MAX}
                 Exactly 2**N-1 -1

           * Maximum values of exact-width unsigned integer types:
          {UINTN_MAX}
                 Exactly 2 **N -1

        * Limits of minimum-width integer types
           * Minimum values of minimum-width signed integer types:
          {INT_LEASTN_MIN}
                 -(2 ** N-1 -1)

           * Maximum values of minimum-width signed integer types:
          {INT_LEASTN_MAX}
                 2 ** N-1 -1

           * Maximum values of minimum-width unsigned integer types:
          {UINT_LEASTN_MAX}
                 2 ** N -1

        * Limits of fastest minimum-width integer types
           * Minimum values of fastest minimum-width signed integer types:
          {INT_FASTN_MIN}
                 -(2 ** N-1 -1)

           * Maximum values of fastest minimum-width signed integer types:
          {INT_FASTN_MAX}
                 2 ** N-1 -1

           * Maximum values of fastest minimum-width unsigned integer types:
          {UINT_FASTN_MAX}
                 2 ** N -1

        * Limits of integer types capable of holding object pointers
           * Minimum value of pointer-holding signed integer type:
          {INTPTR_MIN}
                 -(2 ** 15 -1)

           * Maximum value of pointer-holding signed integer type:
          {INTPTR_MAX}
                 2 ** 15 -1

           * Maximum value of pointer-holding unsigned integer type:
          {UINTPTR_MAX}
                 2 ** 16 -1

        * Limits of greatest-width integer types
           * Minimum value of greatest-width signed integer type:
          {INTMAX_MIN}
                 -(2 ** 63 -1)

           * Maximum value of greatest-width signed integer type:
          {INTMAX_MAX}
                 2 ** 63 -1

           * Maximum value of greatest-width unsigned integer type:
          {UINTMAX_MAX}
                 2 ** 64 -1

   Limits of Other Integer Types
       The following macros specify the minimum and maximum limits of  integer
       types corresponding to types defined in other standard headers.
       Each  instance  of these macros shall be replaced by a constant expres-
       sion suitable for use in #if preprocessing directives, and this expres-
       sion  shall have the same type as would an expression that is an object
       of the corresponding type converted according  to  the  integer  promo-
       tions. Its implementation-defined value shall be equal to or greater in
       magnitude (absolute value) than the corresponding  value  given  below,
       with the same sign.
        * Limits of ptrdiff_t:
       {PTRDIFF_MIN}
              -65535
       {PTRDIFF_MAX}
              +65535

        * Limits of sig_atomic_t:
       {SIG_ATOMIC_MIN}
              See below.
       {SIG_ATOMIC_MAX}
              See below.

        * Limit of size_t:
       {SIZE_MAX}
              65535

        * Limits of wchar_t:
       {WCHAR_MIN}
              See below.
       {WCHAR_MAX}
              See below.

        * Limits of wint_t:
       {WINT_MIN}
              See below.
       {WINT_MAX}
              See below.

       If  sig_atomic_t  (see  the  <signal.h>  header) is defined as a signed
       integer type, the value of {SIG_ATOMIC_MIN} shall be  no  greater  than
       -127  and the value of {SIG_ATOMIC_MAX} shall be no less than 127; oth-
       erwise, sig_atomic_t shall be defined as an unsigned integer type,  and
       the   value   of   {SIG_ATOMIC_MIN}   shall  be  0  and  the  value  of
       {SIG_ATOMIC_MAX} shall be no less than 255.
       If wchar_t (see the <stddef.h> header) is defined as a  signed  integer
       type,  the  value  of {WCHAR_MIN} shall be no greater than -127 and the
       value of {WCHAR_MAX} shall be no  less  than  127;  otherwise,  wchar_t
       shall  be  defined  as  an  unsigned  integer  type,  and  the value of
       {WCHAR_MIN} shall be 0 and the value of {WCHAR_MAX} shall  be  no  less
       than 255.
       If  wint_t  (see  the  <wchar.h> header) is defined as a signed integer
       type, the value of {WINT_MIN} shall be no greater than -32767  and  the
       value  of  {WINT_MAX}  shall  be  no less than 32767; otherwise, wint_t
       shall be defined  as  an  unsigned  integer  type,  and  the  value  of
       {WINT_MIN} shall be 0 and the value of {WINT_MAX} shall be no less than
       65535.
   Macros for Integer Constant Expressions
       The following macros expand to integer  constant  expressions  suitable
       for initializing objects that have integer types corresponding to types
       defined in the <stdint.h> header. Each macro name corresponds to a sim-
       ilar  type  name listed under Minimum-width integer types and Greatest-
       width integer types.
       Each invocation of one of these macros shall expand to an integer  con-
       stant  expression suitable for use in #if preprocessing directives. The
       type of the expression shall have the same type as would an  expression
       that  is an object of the corresponding type converted according to the
       integer promotions.  The value of the expression shall be that  of  the
       argument.
       The argument in any instance of these macros shall be a decimal, octal,
       or hexadecimal constant with a value that does not  exceed  the  limits
       for the corresponding type.
        * Macros for minimum-width integer constant expressions
       The macro INTN_C( value) shall expand to an integer constant expression
       corresponding to the type int_least N _t.  The  macro  UINTN_C(  value)
       shall  expand  to  an  integer constant expression corresponding to the
       type uint_least N _t. For example, if uint_least64_t is a name for  the
       type unsigned long long, then UINT64_C(0x123) might expand to the inte-
       ger constant 0x123ULL.
        * Macros for greatest-width integer constant expressions
       The following macro expands to an integer  constant  expression  having
       the  value  specified  by  its  argument  and  the  type intmax_t: INT-
       MAX_C(value)
       The following macro expands to an integer  constant  expression  having
       the  value  specified  by  its  argument  and the type uintmax_t: UINT-
       MAX_C(value)
       The following sections are informative.
APPLICATION USAGE
       None.
RATIONALE
       The <stdint.h> header is a subset of the <inttypes.h> header more suit-
       able  for use in freestanding environments, which might not support the
       formatted I/O functions. In some environments, if the formatted conver-
       sion  support  is  not  wanted,  using this header instead of the <int-
       types.h> header avoids defining such a large number of macros.
       As a consequence of adding int8_t, the following are true:
        * A byte is exactly 8 bits.
        * {CHAR_BIT}  has  the  value  8,  {SCHAR_MAX}  has  the  value   127,
          {SCHAR_MIN}  has  the  value  -127  or -128, and {UCHAR_MAX} has the
          value 255.
FUTURE DIRECTIONS
       typedef names beginning with int or uint and  ending  with  _t  may  be
       added to the types defined in the <stdint.h> header. Macro names begin-
       ning with INT or UINT and ending with _MAX, _MIN, or _C may be added to
       the macros defined in the <stdint.h> header.
SEE ALSO
       <inttypes.h>, <signal.h>, <stddef.h>, <wchar.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE and
       The  Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be  obtained  online
       at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                       <stdint.h>(0P)