       
SYNOPSIS
       #include <sys/socket.h>

DESCRIPTION
       The  <sys/'socket'.h> header shall define the type 'socklen_t', which is an
       integer type of width of at least 32 bits; see APPLICATION USAGE.

       The <sys/socket.h>  header  shall  define  the  unsigned  integer  type
       'sa_family_t'.

       The  <sys/socket.h>  header  shall  define  the 'sockaddr' structure that
       includes at least the following members:


              sa_family_t  'sa_family'  Address family.
              char         'sa_data'[]  Socket address (variable-length data).

       The sockaddr structure is used to define a socket address which is used
       in the bind(), connect(), getpeername(), getsockname(), recvfrom(), and
       sendto() functions.

       The <sys/socket.h> header shall define the 'sockaddr_storage'  structure.
       This structure shall be:

        * Large  enough to accommodate all supported protocol-specific address
          structures


        * Aligned at an appropriate boundary so that pointers  to  it  can  be
          cast as pointers to protocol-specific address structures and used to
          access the fields of those structures without alignment problems


       The sockaddr_storage structure shall contain  at  least  the  following
       members:


              sa_family_t   'ss_family'

       When  a sockaddr_storage structure is cast as a sockaddr structure, the
       ss_family field of the sockaddr_storage structure shall  map  onto  the
       sa_family  field  of  the  sockaddr  structure. When a sockaddr_storage
       structure is cast as a protocol-specific address structure, the ss_fam-
       ily  field  shall  map  onto  a field of that structure that is of type
       sa_family_t and that identifies the protocol's address family.

       The <sys/socket.h>  header  shall  define  the  'msghdr'  structure  that
       includes at least the following members:


              void          *'msg_name'        Optional address.
              socklen_t      'msg_namelen'     Size of address.
              struct iovec  *'msg_iov'         Scatter/gather array.
              int            'msg_iovlen'      Members in msg_iov.
              void          *'msg_control'     Ancillary data; see below.
              socklen_t      'msg_controllen'  Ancillary data buffer len.
              int            'msg_flags'       Flags on received message.

       The  msghdr  structure  is used to minimize the number of directly sup-
       plied parameters to the recvmsg() and sendmsg() functions.  This struc-
       ture is used as a value- result parameter in the recvmsg() function and
       value only for the sendmsg() function.

       The iovec structure shall be defined as described in <sys/uio.h> .

       The <sys/socket.h> header  shall  define  the  'cmsghdr'  structure  that
       includes at least the following members:


              socklen_t  'cmsg_len'    Data byte count, including the cmsghdr.
              int        'cmsg_level'  Originating protocol.
              int        'cmsg_type'   Protocol-specific type.

       The  cmsghdr  structure  is  used  for storage of ancillary data object
       information.

       Ancillary data consists of a sequence of pairs, each  consisting  of  a
       cmsghdr structure followed by a data array. The data array contains the
       ancillary data message, and the cmsghdr structure contains  descriptive
       information that allows an application to correctly parse the data.

       The  values for cmsg_level shall be legal values for the level argument
       to the getsockopt() and setsockopt() functions. The  system  documenta-
       tion  shall  specify the cmsg_type definitions for the supported proto-
       cols.

       Ancillary data is also possible at the socket level. The <sys/socket.h>
       header  defines the following macro for use as the cmsg_type value when
       cmsg_level is 'SOL_SOCKET':

       'SCM_RIGHTS'
              Indicates that the data array contains the access rights  to  be
              sent or received.


       The  <sys/socket.h>  header defines the following macros to gain access
       to the data arrays in the ancillary  data  associated  with  a  message
       header:

       'CMSG_DATA'(cmsg)

              If  the argument is a pointer to a cmsghdr structure, this macro
              shall return an unsigned character pointer  to  the  data  array
              associated with the cmsghdr structure.

       'CMSG_NXTHDR'(mhdr,cmsg)

              If the first argument is a pointer to a msghdr structure and the
              second argument is a pointer  to  a  cmsghdr  structure  in  the
              ancillary  data  pointed  to  by  the  msg_control field of that
              msghdr structure, this macro shall return a pointer to the  next
              cmsghdr  structure,  or  a null pointer if this structure is the
              last cmsghdr in the ancillary data.

       'CMSG_FIRSTHDR'(mhdr)

              If the argument is a pointer to a msghdr structure,  this  macro
              shall  return  a  pointer  to the first cmsghdr structure in the
              ancillary data associated with this msghdr structure, or a  null
              pointer if there is no ancillary data associated with the msghdr
              structure.


       The <sys/socket.h>  header  shall  define  the  'linger'  structure  that
       includes at least the following members:


              int  'l_onoff'   Indicates whether linger option is enabled.
              int  'l_linger'  Linger time, in seconds.

       The  <sys/socket.h> header shall define the following macros, with dis-
       tinct integer values:

       'SOCK_DGRAM'
              Datagram socket.

       'SOCK_RAW'
              Raw Protocol Interface.

       'SOCK_SEQPACKET'
              Sequenced-packet socket.

       'SOCK_STREAM'
              Byte-stream socket.


       The <sys/socket.h> header shall define the following macro for  use  as
       the level argument of setsockopt() and getsockopt().

       'SOL_SOCKET'
              Options to be accessed at socket level, not protocol level.


       The  <sys/socket.h> header shall define the following macros, with dis-
       tinct integer values, for use as the option_name argument  in  getsock-
       opt() or setsockopt() calls:

       'SO_ACCEPTCONN'
              Socket is accepting connections.

       'SO_BROADCAST'
              Transmission of broadcast messages is supported.

       'SO_DEBUG'
              Debugging information is being recorded.

       'SO_DONTROUTE'
              Bypass normal routing.

       'SO_ERROR'
              Socket error status.

       'SO_KEEPALIVE'
              Connections are kept alive with periodic messages.

       'SO_LINGER'
              Socket lingers on close.

       'SO_OOBINLINE'
              Out-of-band data is transmitted in line.

       'SO_RCVBUF'
              Receive buffer size.

       'SO_RCVLOWAT'
              Receive ``low water mark''.

       'SO_RCVTIMEO'
              Receive timeout.

       'SO_REUSEADDR'
              Reuse of local addresses is supported.

       'SO_SNDBUF'
              Send buffer size.

       'SO_SNDLOWAT'
              Send ``low water mark''.

       'SO_SNDTIMEO'
              Send timeout.

       'SO_TYPE'
              Socket type.


       The <sys/socket.h> header shall define the following macro as the maxi-
       mum backlog queue length which may be specified by the backlog field of
       the listen() function:

       'SOMAXCONN'
              The maximum backlog queue length.


       The  <sys/socket.h> header shall define the following macros, with dis-
       tinct integer values, for use as the valid  values  for  the  'msg_flags'
       field  in  the  msghdr structure, or the flags parameter in recvfrom(),
       recvmsg(), sendmsg(), or sendto() calls:

       'MSG_CTRUNC'
              Control data truncated.

       'MSG_DONTROUTE'
              Send without using routing tables.

       'MSG_EOR'
              Terminates a record (if supported by the protocol).

       'MSG_OOB'
              Out-of-band data.

       'MSG_PEEK'
              Leave received data in queue.

       'MSG_TRUNC'
              Normal data truncated.

       'MSG_WAITALL'
              Attempt to fill the read buffer.


       The <sys/socket.h> header shall define the following macros, with  dis-
       tinct integer values:

       'AF_INET'
              Internet domain sockets for use with IPv4 addresses.

       'AF_INET6'
              Internet domain sockets for use with IPv6 addresses.

       'AF_UNIX'
              UNIX domain sockets.

       'AF_UNSPEC'
              Unspecified.


       The  <sys/socket.h> header shall define the following macros, with dis-
       tinct integer values:

       'SHUT_RD'
              Disables further receive operations.

       'SHUT_RDWR'
              Disables further send and receive operations.

       'SHUT_WR'
              Disables further send operations.


       
SYNOPSIS
       #include <spawn.h>

DESCRIPTION
       The   <'spawn'.h>   header   shall   define   the  'posix_spawnattr_t'  and
       'posix_spawn_file_actions_t' types used in performing spawn operations.

       The <spawn.h> header shall define the  flags  that  may  be  set  in  a
       posix_spawnattr_t object using the 'posix_spawnattr_setflags'() function:


       'POSIX_SPAWN_RESETIDS'
       'POSIX_SPAWN_SETPGROUP'

       'POSIX_SPAWN_SETSCHEDPARAM'
       'POSIX_SPAWN_SETSCHEDULER'

       'POSIX_SPAWN_SETSIGDEF'
       'POSIX_SPAWN_SETSIGMASK'

       
SYNOPSIS
       #include <sys/stat.h>

DESCRIPTION
       The <sys/stat.h> header shall define the structure of the data returned
       by the functions fstat(), lstat(), and stat().

       The 'stat' structure shall contain at least the following members:


              dev_t     'st_dev'     Device ID of device containing file.
              ino_t     'st_ino'     File serial number.
              mode_t    'st_mode'    Mode of file (see below).
              nlink_t   'st_nlink'   Number of hard links to the file.
              uid_t     'st_uid'     User ID of file.
              gid_t     'st_gid'     Group ID of file.

              dev_t     'st_rdev'    Device ID (if file is character or block special).

              off_t     'st_size'    For regular files, the file size in bytes.
                                   For symbolic links, the length in bytes of the
                                   pathname contained in the symbolic link.

                                   For a shared memory object, the length in bytes.


                                   For a typed memory object, the length in bytes.

                                   For other file types, the use of this field is
                                   unspecified.
              time_t    'st_atime'   Time of last access.
              time_t    'st_mtime'   Time of last data modification.
              time_t    'st_ctime'   Time of last status change.

              blksize_t 'st_blksize' A file system-specific preferred I/O block size for
                                   this object. In some file system types, this may
                                   vary from file to file.
              blkcnt_t  'st_blocks'  Number of blocks allocated for this object.


       The st_ino and st_dev fields taken together uniquely identify the  file
       within  the  system.  The  blkcnt_t,  blksize_t,  dev_t, ino_t, mode_t,
       nlink_t, uid_t, gid_t, off_t, and time_t  types  shall  be  defined  as
       described  in <sys/types.h> . Times shall be given in seconds since the
       Epoch.

       Unless otherwise specified,  the  structure  members  st_mode,  st_ino,
       st_dev,  st_uid,  st_gid,  st_atime,  st_ctime, and st_mtime shall have
       meaningful values for all file types defined in IEEE Std 1003.1-2001.

       For symbolic links, the st_mode member shall contain meaningful  infor-
       mation,  which  can  be used with the file type macros described below,
       that take a mode argument. The st_size member shall contain the length,
       in  bytes,  of  the  pathname contained in the symbolic link. File mode
       bits and the contents of the remaining members of  the  stat  structure
       are  unspecified.  The value returned in the st_size field shall be the
       length of the contents of the symbolic link,  and  shall  not  count  a
       trailing null if one is present.

       The  following  symbolic names for the values of type 'mode_t' shall also
       be defined.

       File type:

       'S_IFMT' Type of file.

       'S_IFBLK'
              Block special.

       'S_IFCHR'
              Character special.

       'S_IFIFO'
              FIFO special.

       'S_IFREG'
              Regular.

       'S_IFDIR'
              Directory.

       'S_IFLNK'
              Symbolic link.

       'S_IFSOCK'
              Socket.



       File mode bits:

       'S_IRWXU'
              Read, write, execute/search by owner.

       'S_IRUSR'
              Read permission, owner.

       'S_IWUSR'
              Write permission, owner.

       'S_IXUSR'
              Execute/search permission, owner.


       'S_IRWXG'
              Read, write, execute/search by group.

       'S_IRGRP'
              Read permission, group.

       'S_IWGRP'
              Write permission, group.

       'S_IXGRP'
              Execute/search permission, group.


       'S_IRWXO'
              Read, write, execute/search by others.

       'S_IROTH'
              Read permission, others.

       'S_IWOTH'
              Write permission, others.

       'S_IXOTH'
              Execute/search permission, others.


       'S_ISUID'
              Set-user-ID on execution.

       'S_ISGID'
              Set-group-ID on execution.

       'S_ISVTX'
              On directories, restricted deletion flag.


       The bits  defined  by  S_IRUSR,  S_IWUSR,  S_IXUSR,  S_IRGRP,  S_IWGRP,
       S_IXGRP,  S_IROTH,  S_IWOTH,  S_IXOTH, S_ISUID, S_ISGID,    and S_ISVTX
        shall be unique.

       'S_IRWXU' is the bitwise-inclusive OR of S_IRUSR, S_IWUSR, and S_IXUSR.

       'S_IRWXG' is the bitwise-inclusive OR of S_IRGRP, S_IWGRP, and S_IXGRP.

       'S_IRWXO' is the bitwise-inclusive OR of S_IROTH, S_IWOTH, and S_IXOTH.

       Implementations may OR other implementation-defined bits into  S_IRWXU,
       S_IRWXG,  and S_IRWXO, but they shall not overlap any of the other bits
       defined in this volume of  IEEE Std 1003.1-2001.  The  file  permission
       bits  are defined to be those corresponding to the bitwise-inclusive OR
       of S_IRWXU, S_IRWXG, and S_IRWXO.

       The following macros shall be provided to test whether a file is of the
       specified  type.  The  value  m  supplied to the macros is the value of
       st_mode from a stat structure.  The macro shall evaluate to a  non-zero
       value if the test is true; 0 if the test is false.

       'S_ISBLK'(m)
              Test for a block special file.

       'S_ISCHR'(m)
              Test for a character special file.

       'S_ISDIR'(m)
              Test for a directory.

       S_ISFIFO(m)
              Test for a pipe or FIFO special file.

       'S_ISREG'(m)
              Test for a regular file.

       'S_ISLNK'(m)
              Test for a symbolic link.

       'S_ISSOCK'(m)
              Test for a socket.


       The  implementation may implement message queues, semaphores, or shared
       memory objects as distinct file types. The following  macros  shall  be
       provided  to test whether a file is of the specified type. The value of
       the buf argument supplied to the macros is a pointer to a  stat  struc-
       ture.  The  macro  shall  evaluate to a non-zero value if the specified
       object is implemented as a distinct file type and  the  specified  file
       type  is  contained in the stat structure referenced by buf. Otherwise,
       the macro shall evaluate to zero.

       'S_TYPEISMQ'(buf)
              Test for a message queue.

       'S_TYPEISSEM'(buf)
              Test for a semaphore.

       'S_TYPEISSHM'(buf)
              Test for a shared memory object.


       The implementation may implement typed memory objects as distinct  file
       types,  and  the  following  macro  shall test whether a file is of the
       specified type. The value of the buf argument supplied to the macros is
       a  pointer to a stat structure.  The macro shall evaluate to a non-zero
       value if the specified object is implemented as a  distinct  file  type
       and  the  specified file type is contained in the stat structure refer-
       enced by buf.  Otherwise, the macro shall evaluate to zero.

       'S_TYPEISTMO'(buf)
              Test macro for a typed memory object.


       
SYNOPSIS
       #include <sys/statvfs.h>

DESCRIPTION
       The  <sys/statvfs.h>  header  shall  define  the 'statvfs' structure that
       includes at least the following members:


              unsigned long 'f_bsize'    File system block size.
              unsigned long 'f_frsize'   Fundamental file system block size.
              fsblkcnt_t    'f_blocks'   Total number of blocks on file system in units of f_frsize.
              fsblkcnt_t    'f_bfree'    Total number of free blocks.
              fsblkcnt_t    'f_bavail'   Number of free blocks available to
                                       non-privileged process.
              fsfilcnt_t    'f_files'    Total number of file serial numbers.
              fsfilcnt_t    'f_ffree'    Total number of free file serial numbers.
              fsfilcnt_t    'f_favail'   Number of file serial numbers available to
                                       non-privileged process.
              unsigned long 'f_fsid'     File system ID.
              unsigned long 'f_flag'     Bit mask of f_flag values.
              unsigned long 'f_namemax'  Maximum filename length.

       The fsblkcnt_t and fsfilcnt_t types shall be defined  as  described  in
       <sys/types.h> .

       The following flags for the 'f_flag' member shall be defined:

       'ST_RDONLY'
              Read-only file system.

       'ST_NOSUID'
              Does not support the semantics of the ST_ISUID and ST_ISGID file
              mode bits.


       
SYNOPSIS
       #include <stdarg.h>

       void 'va_start'(va_list ap, argN);
       void 'va_copy'(va_list dest, va_list src);
       type 'va_arg'(va_list ap, type);
       void 'va_end'(va_list ap);


DESCRIPTION
       The <'stdarg'.h> header shall contain a set of macros which allows porta-
       ble functions that accept variable argument lists to be written.  Func-
       tions  that  have variable argument lists (such as printf()) but do not
       use these macros are inherently non-portable, as different systems  use
       different argument-passing conventions.

       The  type  'va_list'  shall be defined for variables used to traverse the
       list.

       The va_start() macro is invoked to initialize ap to  the  beginning  of
       the list before any calls to va_arg().

       The  va_copy()  macro  initializes  dest  as  a  copy of src, as if the
       va_start() macro had been applied to dest followed by the same sequence
       of  uses of the va_arg() macro as had previously been used to reach the
       present state of src. Neither the va_copy() nor va_start() macro  shall
       be  invoked  to  reinitialize dest without an intervening invocation of
       the va_end() macro for the same dest.

       The object ap may be passed as an argument to another function; if that
       function  invokes the va_arg() macro with parameter ap, the value of ap
       in the calling function is unspecified  and  shall  be  passed  to  the
       va_end() macro prior to any further reference to ap. The parameter argN
       is the identifier of the rightmost parameter in the variable  parameter
       list  in  the function definition (the one just before the ...). If the
       parameter argN is declared with the  register  storage  class,  with  a
       function type or array type, or with a type that is not compatible with
       the type that results after application of the default argument  promo-
       tions, the behavior is undefined.

       The  va_arg()  macro shall return the next argument in the list pointed
       to by ap. Each invocation of va_arg() modifies ap so that the values of
       successive  arguments are returned in turn. The type parameter shall be
       a type name specified such that the type of a pointer to an object that
       has  the  specified  type can be obtained simply by postfixing a '*' to
       type. If there is no actual next argument, or if type is not compatible
       with the type of the actual next argument (as promoted according to the
       default argument promotions), the behavior is undefined, except for the
       following cases:

        * One type is a signed integer type, the other type is the correspond-
          ing unsigned integer type, and the value is  representable  in  both
          types.


        * One  type is a pointer to void and the other is a pointer to a char-
          acter type.


        * Both types are pointers.


       Different types can be mixed, but it is up to the routine to know  what
       type of argument is expected.

       The  va_end()  macro  is  used  to  clean up; it invalidates ap for use
       (unless va_start() or va_copy() is invoked again).

       Each invocation of the va_start() and va_copy() macros shall be matched
       by  a  corresponding invocation of the va_end() macro in the same func-
       tion.

       Multiple traversals, each bracketed by  va_start()  ...  va_end(),  are
       possible.

EXAMPLES
       This example is a possible implementation of execl():


              #include <stdarg.h>


              #define  MAXARGS     31



              /*
               * execl is called by
               * execl(file, arg1, arg2, ..., (char *)(0));
               */
              int execl(const char *file, const char *args, ...)
              {
                  va_list ap;
                  char *array[MAXARGS +1];
                  int argno = 0;


                  va_start(ap, args);
                  while (args != 0 && argno < MAXARGS)
                  {
                      array[argno++] = args;
                      args = va_arg(ap, const char *);
                  }
                  array[argno] = (char *) 0;
                  va_end(ap);
                  return execv(file, array);
              }

       
SYNOPSIS
       #include <stdbool.h>

DESCRIPTION
       The <'stdbool'.h> header shall define the following macros:

       'bool'   Expands to _Bool.

       'true'   Expands to the integer constant 1.

       'false'  Expands to the integer constant 0.

       '__bool_true_false_are_defined'

              Expands to the integer constant 1.


       An application may undefine and then possibly redefine the macros bool,
       true, and false.

       
SYNOPSIS
       #include <stddef.h>

DESCRIPTION
       The <'stddef'.h> header shall define the following macros:

       'NULL'   Null pointer constant.

       'offsetof'(type, member-designator)

              Integer  constant  expression of type size_t, the value of which
              is the offset in bytes to the structure member  (member-designa-
              tor), from the beginning of its structure (type).


       The <stddef.h> header shall define the following types:

       'ptrdiff_t'
              Signed integer type of the result of subtracting two pointers.

       'wchar_t'
              Integer  type whose range of values can represent distinct wide-
              character codes for all members of  the  largest  character  set
              specified  among  the locales supported by the compilation envi-
              ronment: the null character has the code value 0 and each member
              of  the  portable  character  set  has a code value equal to its
              value when used as the lone character in  an  integer  character
              constant.

       'size_t' Unsigned integer type of the result of the sizeof operator.


       The  implementation  shall support one or more programming environments
       in which the widths of ptrdiff_t, size_t, and wchar_t  are  no  greater
       than  the  width of type long.  The names of these programming environ-
       ments can be obtained using the confstr() function or the getconf util-
       ity.

       
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)

