GETNETENT(3N)                                                    GETNETENT(3N)


NAME
     getnetent, getnetent_r, fgetnetent, fgetnetent_r, getnetbyaddr,
     getnetbyaddr_r, getnetbyname, getnetbyname_r, setnetent, endnetent - get
     network entry

SYNOPSIS
     #include <netdb.h>

     struct netent *getnetent(void);

     struct netent *getnetent_r(struct netent *nent, char *buffer, int bufsize);

     struct netent *fgetnetent(FILE *);

     struct netent *fgetnetent_r(FILE *, struct netent *nent, char *buffer, int bufsize);

     struct netent *getnetbyname(const char *name);

     struct netent *getnetbyname_r(const char *name, struct netent *nent, char *buffer, int bufsize);

     struct netent *getnetbyaddr(long net, int type);

     struct netent *getnetbyaddr_r(long net, int type, struct netent *nent, char *buffer, int bufsize);

     void setnetent(int stayopen);

     void endnetent(void);

DESCRIPTION
     Getnetent, fgetnetent, getnetbyname, getnetbyaddr and each of their
     reentrant counterparts each return a pointer to an object with the
     following structure containing the broken-out fields of a line in the
     network data base file, /etc/networks, or some other back-end networks
     database.

          struct    netent {
               char      *n_name;  /* official name of net */
               char      **n_aliases;   /* alias list */
               int       n_addrtype;    /* net number type */
               unsigned 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.

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

     Endnetent closes the file.

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

     The routines fgetnetent and fgetnetent_r will return the next line in the
     supplied file parsed into a struct netent structure.  The file must be in
     the same format as the /etc/networks file.

     The routines getnetent, fgetnetent, getnetbyaddr,  and  getnetbyname  all
     return  pointers  into  static  space  which  is  modified  on each call.
     Reentrant   versions   of   each   routine   getnetent_r,   fgetnetent_r,
     getnetbyaddr_r  and getnetbyname_r.  These routines parse the result into
     supplied space.  They each take  a  pointer  to  a  netent  structure,  a
     pointer to some buffer, and a length for the buffer.

     The routines documented in this file only parse files of the format given
     in  networks(4).   These  can  be  static files on the system such as the
     /etc/networks file, or files supplied dynamically by the  nsd(1M)  daemon
     from some other backend database such as NIS.

NOTE
     The Mips ABI specifies nothing but local files so applications which wish
     to use anything else must compile with libc prior to libnsl in the
     library list.

     When nsd is running changes in the local networks file may not be noticed
     by getnetent() until the enumeration cache file has timed out.

DIAGNOSTICS
     All functions that return struct netent * will return a null (0) pointer
     in the case of EOF or failure.

FILES
     /etc/networks /var/ns/cache/networks.byname.m
     /var/ns/cache/networks.byaddr.m

SEE ALSO
     nsd(1M), networks(4)


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

BUGS
     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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