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GETNETENT(3) BSD Library Functions Manual GETNETENT(3)
NAME
endnetent, getnetbyaddr, getnetbyname, getnetent, setnetent -- get net-work network
work entry
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <netdb.h>
void
endnetent(void);
struct netent *
getnetbyaddr(uint32_t net, int type);
struct netent *
getnetbyname(const char *name);
struct netent *
getnetent(void);
void
setnetent(int stayopen);
DESCRIPTION
The getnetent(), getnetbyname(), and getnetbyaddr() functions each return
a pointer to an object with the following structure containing the bro-ken-out broken-out
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. The type must be AF_INET.
Network numbers are supplied in host order.
FILES
/etc/networks
DIAGNOSTICS
Null pointer (0) returned on EOF or error.
SEE ALSO
networks(5)
RFC 1101
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 functions
tions overwrite it. Only Internet network numbers are currently under-stood. understood.
stood. Expecting network numbers to fit in no more than 32 bits is prob-ably probably
ably naive.
BSD June 4, 1993 BSD
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