inet_pton(3) 맨 페이지 - 윈디하나의 솔라나라

개요

섹션
맨 페이지 이름
검색(S)

inet_pton(3)

INET_PTON(3)               Linux Programmer's Manual              INET_PTON(3)



NAME
       inet_pton - convert IPv4 and IPv6 addresses from text to binary form

SYNOPSIS
       #include <arpa/inet.h>

       int inet_pton(int af, const char *src, void *dst);

DESCRIPTION
       This  function converts the character string src into a network address
       structure in the af address family, then  copies  the  network  address
       structure  to dst.  The af argument must be either AF_INET or AF_INET6.
       dst is written in network byte order.

       The following address families are currently supported:

       AF_INET
              src points to a character  string  containing  an  IPv4  network
              address  in  dotted-decimal format, "ddd.ddd.ddd.ddd", where ddd
              is a decimal number of up to three digits in the range 0 to 255.
              The  address is converted to a struct in_addr and copied to dst,
              which must be sizeof(struct in_addr) (4) bytes (32 bits) long.

       AF_INET6
              src points to a character  string  containing  an  IPv6  network
              address.   The  address  is  converted  to a struct in6_addr and
              copied to dst, which must be sizeof(struct in6_addr) (16)  bytes
              (128  bits) long.  The allowed formats for IPv6 addresses follow
              these rules:

              1. The preferred format is x:x:x:x:x:x:x:x.  This form  consists
                 of  eight  hexadecimal  numbers,  each  of  which expresses a
                 16-bit value (i.e., each x can be up to 4 hex digits).

              2. A series of contiguous zero values in  the  preferred  format
                 can  be abbreviated to ::.  Only one instance of :: can occur
                 in  an  address.    For   example,   the   loopback   address
                 0:0:0:0:0:0:0:1  can  be  abbreviated  as  ::1.  The wildcard
                 address, consisting of all zeros, can be written as ::.

              3. An alternate format is useful for expressing IPv4-mapped IPv6
                 addresses.   This  form  is  written  as x:x:x:x:x:x:d.d.d.d,
                 where the six leading xs are hexadecimal values  that  define
                 the  six most-significant 16-bit pieces of the address (i.e.,
                 96 bits), and the ds express a value in dotted-decimal  nota‐
                 tion  that  defines  the  least  significant  32  bits of the
                 address.    An   example    of    such    an    address    is
                 ::FFFF:204.152.189.116.

              See  RFC  2373 for further details on the representation of IPv6
              addresses.

RETURN VALUE
       inet_pton() returns 1 on success (network address was successfully con‐
       verted).  0 is returned if src does not contain a character string rep‐
       resenting a valid network address in the specified address family.   If
       af does not contain a valid address family, -1 is returned and errno is
       set to EAFNOSUPPORT.

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       allbox;  lb  lb  lb  l  l  l.  Interface Attribute Value T{ inet_pton()
       T}   Thread safety  MT-Safe locale

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

NOTES
       Unlike  inet_aton(3)  and  inet_addr(3),  inet_pton()   supports   IPv6
       addresses.   On the other hand, inet_pton() accepts only IPv4 addresses
       in dotted-decimal notation, whereas inet_aton(3) and inet_addr(3) allow
       the  more general numbers-and-dots notation (hexadecimal and octal num‐
       ber formats, and formats that  don't  require  all  four  bytes  to  be
       explicitly   written).    For  an  interface  that  handles  both  IPv6
       addresses, and IPv4 addresses in numbers-and-dots notation, see  getad‐
       drinfo(3).

BUGS
       AF_INET6  does  not  recognize IPv4 addresses.  An explicit IPv4-mapped
       IPv6 address must be supplied in src instead.

EXAMPLE
       The program below demonstrates the use of inet_pton() and inet_ntop(3).
       Here are some example runs:

           $ ./a.out i6 0:0:0:0:0:0:0:0
           ::
           $ ./a.out i6 1:0:0:0:0:0:0:8
           1::8
           $ ./a.out i6 0:0:0:0:0:FFFF:204.152.189.116
           ::ffff:204.152.189.116

   Program source

       #include <arpa/inet.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>

       int
       main(int argc, char *argv[])
       {
           unsigned char buf[sizeof(struct in6_addr)];
           int domain, s;
           char str[INET6_ADDRSTRLEN];

           if (argc != 3) {
               fprintf(stderr, "Usage: %s {i4|i6|<num>} string\n", argv[0]);
               exit(EXIT_FAILURE);
           }

           domain = (strcmp(argv[1], "i4") == 0) ? AF_INET :
                    (strcmp(argv[1], "i6") == 0) ? AF_INET6 : atoi(argv[1]);

           s = inet_pton(domain, argv[2], buf);
           if (s <= 0) {
               if (s == 0)
                   fprintf(stderr, "Not in presentation format");
               else
                   perror("inet_pton");
               exit(EXIT_FAILURE);
           }

           if (inet_ntop(domain, buf, str, INET6_ADDRSTRLEN) == NULL) {
               perror("inet_ntop");
               exit(EXIT_FAILURE);
           }

           printf("%s\n", str);

           exit(EXIT_SUCCESS);
       }

SEE ALSO
       getaddrinfo(3), inet(3), inet_ntop(3)

COLOPHON
       This  page  is  part of release 5.02 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       https://www.kernel.org/doc/man-pages/.



Linux                             2019-03-06                      INET_PTON(3)
맨 페이지 내용의 저작권은 맨 페이지 작성자에게 있습니다.
RSS ATOM XHTML 5 CSS3