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

       inet_aton,    inet_addr,	   inet_network,   inet_ntoa,	inet_makeaddr,
       inet_lnaof, inet_netof -	Internet address manipulation routines

       #include	<sys/socket.h>
       #include	<netinet/in.h>
       #include	<arpa/inet.h>

       int inet_aton(const char	*cp, struct in_addr *inp);

       in_addr_t inet_addr(const char *cp);

       in_addr_t inet_network(const char *cp);

       char *inet_ntoa(struct in_addr in);

       struct in_addr inet_makeaddr(int	net, int host);

       in_addr_t inet_lnaof(struct in_addr in);

       in_addr_t inet_netof(struct in_addr in);

       inet_aton() converts the	Internet host address  cp  from	 the  standard
       numbers-and-dots	 notation into binary data and stores it in the	struc-
       ture that inp points to.	inet_aton returns nonzero if  the  address  is
       valid, zero if not.

       The  inet_addr()	 function  converts  the Internet host address cp from
       numbers-and-dots	notation into binary data in network byte  order.   If
       the input is invalid, INADDR_NONE (usually -1) is returned.  This is an
       obsolete	interface to inet_aton,	described immediately above; it	is ob-
       solete  because	-1 is a	valid address (, and inet_aton
       provides	a cleaner way to indicate error	return.

       The inet_network() function extracts the	network	number	in  host  byte
       order  from  the	address	cp in numbers-and-dots notation.  If the input
       is invalid, -1 is returned.

       The inet_ntoa() function	converts the Internet host address in given in
       network	byte  order to a string	in standard numbers-and-dots notation.
       The string is returned in a statically allocated	buffer,	 which	subse-
       quent calls will	overwrite.

       The  inet_makeaddr() function makes an Internet host address in network
       byte order by combining the network number net with the	local  address
       host in network net, both in local host byte order.

       The  inet_lnaof()  function  returns the	local host address part	of the
       Internet	address	in.  The local host address is returned	in local  host
       byte order.

       The inet_netof()	function returns the network number part of the	Inter-
       net Address in.	The network number is returned in local	host byte  or-

       The   structure	 in_addr  as  used  in	inet_ntoa(),  inet_makeaddr(),
       inet_lnoaf() and	inet_netof() is	defined	in netinet/in.h	as:

	      struct in_addr {
		      unsigned long int	s_addr;

       Note that on the	i80x86 the host	byte order is Least  Significant  Byte
       first, whereas the network byte order, as used on the Internet, is Most
       Significant Byte	first.

       BSD 4.3

       gethostbyname(3), getnetent(3), inet_ntop(3),  inet_pton(3),  hosts(5),

BSD				  2001-07-25			       INET(3)


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