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);

       unsigned long int inet_addr(const char *cp);

       unsigned long int inet_network(const char *cp);

       char *inet_ntoa(struct in_addr in);

       struct in_addr inet_makeaddr(int net, int host);

       unsigned long int inet_lnaof(struct in_addr in);

       unsigned long int 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 structure 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       obsolete interface to inet_aton, described immediately above; it  is  obsolete  because  -1  is  a  valid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 notation.  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                                             September 3, 1995                                        INET(3)