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Linux 2.6 - man page for inet_ntop (linux section 3posix)

INET_NTOP(P)			    POSIX Programmer's Manual			     INET_NTOP(P)

       inet_ntop, inet_pton - convert IPv4 and IPv6 addresses between binary and text form

       #include <arpa/inet.h>

       const char *inet_ntop(int af, const void *restrict src,
	      char *restrict dst, socklen_t size);
       int inet_pton(int af, const char *restrict src, void *restrict dst);

       The  inet_ntop()  function shall convert a numeric address into a text string suitable for
       presentation. The af argument shall specify the family of the address. This can be AF_INET
	or AF_INET6.  The src argument points to a buffer holding an IPv4 address if the af argu-
       ment is AF_INET,  or an IPv6 address if the af argument is AF_INET6;  the address must  be
       in  network  byte order. The dst argument points to a buffer where the function stores the
       resulting text string; it shall not be NULL. The size argument specifies the size of  this
       buffer,	which  shall  be large enough to hold the text string (INET_ADDRSTRLEN characters
       for IPv4,    INET6_ADDRSTRLEN characters for IPv6).

       The inet_pton() function shall convert an address in its standard text  presentation  form
       into  its  numeric  binary form.  The af argument shall specify the family of the address.
       The AF_INET    and AF_INET6 address families shall be supported. The src  argument  points
       to the string being passed in. The dst argument points to a buffer into which the function
       stores the numeric address; this shall be large enough to hold  the  numeric  address  (32
       bits for AF_INET,  128 bits for AF_INET6).

       If the af argument of inet_pton() is AF_INET, the src string shall be in the standard IPv4
       dotted-decimal form:


       where "ddd" is a one to three digit decimal number between 0 and 255 (see  inet_addr()  ).
       The  inet_pton()  function does not accept other formats (such as the octal numbers, hexa-
       decimal numbers, and fewer than four numbers that inet_addr() accepts).

       If the af argument of inet_pton() is AF_INET6, the src string shall be in one of the  fol-
       lowing standard IPv6 text forms:

	1. The	preferred  form is "x:x:x:x:x:x:x:x" , where the 'x' s are the hexadecimal values
	   of the eight 16-bit pieces of the address. Leading zeros in individual fields  can  be
	   omitted, but there shall be at least one numeral in every field.

	2. A  string  of  contiguous zero fields in the preferred form can be shown as "::" . The
	   "::" can only appear once in an address. Unspecified addresses (  "0:0:0:0:0:0:0:0"	)
	   may be represented simply as "::" .

	3. A  third  form that is sometimes more convenient when dealing with a mixed environment
	   of IPv4 and IPv6 nodes is "x:x:x:x:x:x:d.d.d.d" , where the 'x' s are the  hexadecimal
	   values of the six high-order 16-bit pieces of the address, and the 'd' s are the deci-
	   mal values of the four low-order 8-bit pieces of the address (standard IPv4	represen-

       Note:  A  more extensive description of the standard representations of IPv6 addresses can
	      be found in RFC 2373.

       The inet_ntop() function shall return a pointer to the buffer containing the  text  string
       if the conversion succeeds, and NULL otherwise, and set errno to indicate the error.

       The  inet_pton()  function  shall  return  1  if the conversion succeeds, with the address
       pointed to by dst in network byte order. It shall return 0 if the input	is  not  a  valid
       IPv4  dotted-decimal  string	or  a valid IPv6 address string,  or -1 with errno set to
       [EAFNOSUPPORT] if the af argument is unknown.

       The inet_ntop() and inet_pton() functions shall fail if:


	      The af argument is invalid.

       ENOSPC The size of the inet_ntop() result buffer is inadequate.

       The following sections are informative.





       The Base Definitions volume of IEEE Std 1003.1-2001, <arpa/inet.h>

       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 orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003				     INET_NTOP(P)

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