getnetent(3N)                                       getnetent(3N)



     NAME
          getnetent, getnetbyaddr, getnetbyname, setnetent, endnetent
          - get network entry

     SYNOPSIS
          #include <netdb.h>

          struct netent *getnetent()

          struct netent *getnetbyname(name)
          char *name;

          struct netent *getnetbyaddr(net)
          long net;

          setnetent(stayopen)
          int stayopen;

          endnetent()

     DESCRIPTION
          getnetent, getnetbyname, and getnetbyaddr each return a
          pointer to an object with the following structure, contain-
          ing the broken-out fields of a line in the network data
          base, /etc/networks.

          struct netent {
                 char   *n_name;     /* official name of net */
                 char   **n_aliases; /* alias list */
                 int    n_addrtype;  /* net number type */
                 long   n_net;       /* net number */
          };

          The members of this structure are:

          n_name      The official name of the network.

          n_aliases   A zero terminated list of alternate names for
                      the network.

          n_addrtype  The type of the network number returned;
                      currently only AF_INET.

          n_net       The network number.  Network numbers are re-
                      turned in machine byte order.

          getnetent reads the next line of the file, opening the file
          if necessary.

          setnetent opens and rewinds the file.  If the stayopen flag
          is nonzero, the net data base will not be closed after each
          call to getnetent (either directly, or indirectly through



     April, 1990                                                     1

     getnetent(3N)                                       getnetent(3N)



          one of the other ``getnet'' calls).

          endnetent closes the file.

          getnetbyname and getnetbyaddr sequentially search from the
          beginning of the file until a matching net name or net ad-
          dress is found, or until EOF is encountered.  Network
          numbers are supplied in host order.

     RETURN VALUE
          NULL pointer (0) returned on EOF or error.

     FILES
          /etc/networks

     SEE ALSO
          networks(4N).

     BUGS
          All information is contained in a static area, so it must be
          copied if it is to be saved.  Only Internet network numbers
          are currently understood.  Expecting network numbers to fit
          in no more than 32 bits is probably naive.
































     2                                                     April, 1990