inet_network

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



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

SYNOPSIS
       #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);

DESCRIPTION
       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       an obsolete interface to inet_aton, described immediately above; it is
       obsolete	  because  -1  is  a  valid  address  (255.255.255.255),  and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 nota-
       tion.  The string is returned in a statically allocated buffer,	which
       subsequent 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
       Internet Address in.  The network number is  returned  in  local	 host
       byte order.

       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.

CONFORMING TO
       BSD 4.3

SEE ALSO
       gethostbyname(3), getnetent(3), inet_ntop(3), inet_pton(3),  hosts(5),
       networks(5)



BSD				  2001-07-25			      INET(3)