inet(3N)                                                    inet(3N)


       NAME
             inet: inet_addr, inet_network, inet_makeaddr, inet_lnaof,
             inet_netof, inet_ntoa - Internet address manipulation

       SYNOPSIS
             cc [options] file -lsocket -lnsl
             #include <netinet/in.h>
             #include <arpa/inet.h>
             unsigned long inet_addr(char *cp);
             unsigned long inet_network(char *cp);
             struct in_addr inet_makeaddr(unsigned long net, unsigned long lna);
             int inet_lnaof(struct in_addr in);
             int inet_netof(struct in_addr in);
             cc [options] file -lnsl
             #include <netinet/in.h>
             #include <arpa/inet.h>
             char *inet_ntoa(struct in_addr in);

       DESCRIPTION
             The routines inet_addr and inet_network each interpret
             character strings representing numbers expressed in the
             Internet standard ``.'' (``dot'') notation, returning numbers
             suitable for use as Internet addresses and Internet network
             numbers, respectively.

             The routine inet_makeaddr takes an Internet network number and
             a local network address and constructs an Internet address
             from it.

             The routines inet_netof and inet_lnaof break apart Internet
             host addresses, returning the network number and local network
             address part, respectively.

             The routine inet_ntoa returns a pointer to a string in the
             base 256 notation ``d.d.d.d'' described below.

             All Internet addresses are in network byte order.  All network
             numbers and local address parts are in host byte order.

          Return Values
             The value -1 is returned by inet_addr and inet_network for
             malformed requests.

       USAGE
             Values specified using the ``.'' notation take one of the
             following forms:


                           Copyright 1994 Novell, Inc.               Page 1

      inet(3N)                                                    inet(3N)


                  a.b.c.d
                  a.b.c
                  a.b
                  a

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

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

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

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

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

      REFERENCES
            gethostent(3N), getnetent(3N), hosts(4), networks(4)

      NOTICES
            The return value from inet_ntoa points to static information
            which is overwritten in each call.  For multi-threaded
            applications, information is maintained on a per-thread basis.











                          Copyright 1994 Novell, Inc.               Page 2