GETNETENT(3) MachTen Programmer’s Manual GETNETENT(3)
NAME
getnetent, getnetbyaddr, getnetbyname, setnetent, endnetent
- get network
entry
SYNOPSIS
#include <netdb.h>
struct netent *
getnetent()
struct netent *
getnetbyname(char *name)
struct netent *
getnetbyaddr(long net, int type)
setnetent(int stayopen)
endnetent()
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 data base,
/etc/networks.
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.
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. Network numbers
are supplied
in host order.
FILES
/etc/networks
DIAGNOSTICS
Null pointer (0) returned on EOF or error.
SEE ALSO
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 prob-
ably naive.
4.2 Berkeley Distribution June 4, 1993 2