GETNETENT

Section: Network Functions (3N)
Updated: May 19, 1986
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NAME

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

SYNOPSIS

#include <netdb.h>

struct netent *getnetent()

struct netent *getnetbyname(name)
char *name;

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

setnetent(stayopen)
int stayopen;

endnetent()

DESCRIPTION

Getnetent, getnetbyname, and getnetbyaddr each return a pointer to an object with the following structure containing the broken-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.

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.

FILES

/etc/networks

DIAGNOSTICS

Null pointer (0) returned on EOF or error.

BUGS

All information is contained in a static area so it must be copied if it is to be saved. Only Internet network numbers are currently understood. Expecting network numbers to fit in no more than 32 bits is probably naive.

This document was created by man2html, using the manual pages.
Time: 04:51:46 GMT, January 31, 2023