getnetent()

NAME

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

SYNOPSIS

#include <netdb.h>


struct netent * getnetent (void)
struct netent * getnetbyname (char *name)
struct netent * getnetbyaddr (long net, int type)
int setnetent (int stayopen)
int endnetent (void)

DESCRIPTION

The getnetent(3), getnetbyname(3), and getnetbyaddr(3) functions each return a pointer to an object with the following structure containing the broken-out fields of a line in the network data base:
%WINDIR%/system32/drivers/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(3) function reads the next line of the file, opening the file if necessary.

The setnetent(3) 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(3) or getnetbyaddr(3).

The endnetent(3) function closes the file.

The getnetbyname(3) function and getnetbyaddr(3) search sequentially from the beginning of the file until a matching net name or net address and type is found, or until the end of file (EOF) is encountered. Network numbers are supplied in host order.

FILES

%WINDIR%system32/drivers/etc/networks

The network database; the value of %WINDIR% is the installation directory for Windows, typically /dev/fs/C/WINNT.

DIAGNOSTICS

Null pointer (0) returned on EOF or error.

NOTES

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 functions overwrite it. Only Internet network numbers are currently understood. Expecting network numbers to fit in no more than 32 bits is probably unrealistic.