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,
     containing 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 returned in
          machine byte order.

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



January 1992                                                    1

getnetent(3N)                                       getnetent(3N)



     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
     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
     address is found, or until EOF is encountered.  Network
     numbers are supplied in host order.

STATUS MESSAGES AND VALUES
     A null pointer (0) is returned on EOF or error.

LIMITATIONS
     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.

FILES
     /etc/networks
          File containing list of networks

SEE ALSO
     networks(4N)




























2                                                    January 1992