getnetent(3N)                 4 BSD                 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, type)
     long net, type;

     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.

     CX/UX supports both a  proprietary  version  and  an  88open
     Object  Compatibility Standard Networking Supplement (OCSNS)
     version of getnetbyname and getnetbyaddr.   The  OCSNS  ver-
     sions  of  these  functions  check  for the existence of the
     function /etc/bcs_cat and if it exists and has  proper  exe-
     cute  permission, will issue a popen(3S) call of the command



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getnetent(3N)                 4 BSD                 getnetent(3N)



     /etc/bcs_cat networks.  If the  file  does  not  exist,  the
     functions will access the /etc/networks file.

     getnetent reads the next line  of  the  /etc/networks  file,
     opening  the  file if necessary and returning a pointer to a
     netent structure containing the file entry.

     Setnetent opens and rewinds the /etc/networks file.  If  the
     stayopen  flag  is  non-zero,  the net data base will not be
     closed after each call to getnetent, getnetbyname,  or  get-
     netbyaddr.

     Endnetent closes the file /etc/networks and clears the stay-
     open flag.

     The  functions  getnetent,  setnetent,  and  endnetent   are
     defined  in  the  88open  OCSNS.  Their functionality is the
     same as described above.

     Both versions of 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.  The type param-
     eter for getnetbyaddr must be  AF_INET.   The  88open  OCSNS
     versions  of the above files may be accessed through special
     OCS options passed to cc(1) and/or ld(1).

FILES
     /etc/networks

SEE ALSO
     bcs_cat(1), networks(4C)

DIAGNOSTICS
     Null pointer (0) returned on EOF or error.

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.














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