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# getnetent

    GETNETENT(3)            System Library Functions Manual           GETNETENT(3)

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

    SYNOPSIS
         #include <netdb.h>

         struct netent *
         getnetent(void);

         struct netent *
         getnetbyname(char *name);

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

         void
         setnetent(int stayopen);

         void
         endnetent(void);

    DESCRIPTION
         The getnetent(), getnetbyname(), and getnetbyaddr() functions each return
         a pointer to an object with the following structure containing the bro-
         ken-out fields of a line in the network database, /etc/networks.

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

         The getnetent() function reads the next line of the file, opening the
         file if necessary.

         The setnetent() function opens and rewinds the file.  If the stayopen
         flag is non-zero, the net database will not be closed after each call to
         getnetbyname() or getnetbyaddr().

         The endnetent() function closes the file.

         The getnetbyname() and getnetbyaddr() functions search the domain name
         server if the system is configured to use one.  If the search fails, or
         no name server is configured, they 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.

    FILES
         /etc/networks

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

    SEE ALSO
         resolver(3), networks(5)

    HISTORY
         The getnetent(), getnetbyaddr(), getnetbyname(), setnetent(), and
         endnetent() functions appeared in 4.2BSD.

    BUGS
         The data space used by these functions is static; if future use requires
         the data, it should be copied before any subsequent calls to these func-
         tions overwrite it.  Only Internet network numbers are currently under-
         stood.  Expecting network numbers to fit in no more than 32 bits is
         naive.

    BSD                             March 13, 1997                             BSD

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