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.

structnetent {
char*n_name;/* official name of net */
char**n_aliases;/* alias list */
intn_addrtype;/* net number type */
unsigned longn_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

SEE ALSO

networks(5)

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. 

NOTE

There are two versions of the primitives documented in this manual entry:  a vanilla version and a Yellow Pages version.  The programmatic interface of both versions is identical.  The vanilla version gets its information from an ASCII file in /etc. The Yellow Pages version knows about Sun’s Yellow Pages distributed lookup service. If you want the Yellow Pages version, link the program according to the instructions for (3Y) primitives as described in intro(3). Refer to ypserv(1M) and the NFS User’s Guide for more information about the Yellow Pages. 

Version 2.5  —  April 22, 1987