NAME

       inet_addr, inet_ntoa - IPv4 address manipulation

SYNOPSIS

       #include <arpa/inet.h>

       in_addr_t inet_addr(const char *cp);
       char *inet_ntoa(struct in_addr in);

DESCRIPTION

       The  inet_addr()  function shall convert the string pointed to by cp, in the standard IPv4 dotted decimal
       notation, to an integer value suitable for use as an Internet address.

       The inet_ntoa() function shall convert the Internet host address specified by  in  to  a  string  in  the
       Internet standard dot notation.

       The  inet_ntoa()  function  need not be reentrant. A function that is not required to be reentrant is not
       required to be thread-safe.

       All Internet addresses shall be returned in network order (bytes ordered from left to right).

       Values specified using IPv4 dotted decimal notation take one of the following forms:

       a.b.c.d
              When four parts are specified, each shall be interpreted as a byte of data and assigned, from left
              to right, to the four bytes of an Internet address.

       a.b.c  When  a  three-part  address is specified, the last part shall be interpreted as a 16-bit quantity
              and placed in the rightmost two bytes of the network address. This makes  the  three-part  address
              format convenient for specifying Class B network addresses as "128.net.host" .

       a.b    When  a  two-part address is supplied, the last part shall be interpreted as a 24-bit quantity and
              placed in the rightmost three bytes of the network address. This makes the two-part address format
              convenient for specifying Class A network addresses as "net.host" .

       a      When only one part is given, the value shall be stored directly in the network address without any
              byte rearrangement.

       All numbers supplied as parts in IPv4 dotted decimal notation may be decimal, octal, or  hexadecimal,  as
       specified  in  the  ISO C standard (that is, a leading 0x or 0X implies hexadecimal; otherwise, a leading
       '0' implies octal; otherwise, the number is interpreted as decimal).

RETURN VALUE

       Upon successful completion, inet_addr() shall return the Internet address. Otherwise, it shall  return  (
       in_addr_t)(-1).

       The inet_ntoa() function shall return a pointer to the network address in Internet standard dot notation.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The  return  value of inet_ntoa() may point to static data that may be overwritten by subsequent calls to
       inet_ntoa().

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       endhostent() , endnetent() , the Base Definitions volume of IEEE Std 1003.1-2001, <arpa/inet.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 .