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GETNETENT(3)             BSD Library Functions Manual             GETNETENT(3)

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

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <netdb.h>

     struct netent *
     getnetent(void);

     struct netent *
     getnetbyname(const char *name);

     struct netent *
     getnetbyaddr(uint32_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 describing an internet network.  This structure contains information obtained
     from opendirectoryd(8), including records in /etc/networks.

           struct  netent {
                   char            *n_name;        /* official name of net */
                   char            **n_aliases;    /* alias list */
                   int             n_addrtype;     /* net number type */
                   uint32_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 data
     base will not be closed after each call to getnetbyname() or getnetbyaddr().

     The endnetent() function closes the file.

     The getnetbyname() function 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.  The type argument
     must be AF_INET.  Network numbers are supplied in host order.

FILES
     /etc/networks
     /etc/resolv.conf

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

SEE ALSO
     networks(5)

     RFC 11_1

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

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

BSD                              June 4, 1993                              BSD