GETNETENT(3) Linux Programmer's Manual GETNETENT(3)

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

#include <netdb.h>

struct netent *getnetent(void);

struct netent *getnetbyname(const char *name);

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

void setnetent(int stayopen);

void endnetent(void);

The getnetent() function reads the next line from the file /etc/networks and returns a structure netent containing the broken out fields from the line. The /etc/networks file is opened if necessary.

The getnetbyname() function returns a netent structure for the line from /etc/networks that matches the network name.

The getnetbyaddr() function returns a netent structure for the line that matches the network number net of type type.

The setnetent() function opens and rewinds the /etc/networks file. If stayopen is true (1), then the file will not be closed between calls to getnetbyname() and getnetbyaddr().

The endnetent() function closes /etc/networks.

The netent structure is defined in <netdb.h> as follows:


struct netent {
	char	*n_name;		/* official network name */
	char	**n_aliases;		/* alias list */
	int	n_addrtype;		/* net address type */
	unsigned long int n_net;	/* network number */
}

The members of the netent structure are:

The official name of the network.
A zero terminated list of alternative names for the network.
The type of the network number; always AF_INET.
The network number in host byte order.

The getnetent(), getnetbyname() and getnetbyaddr() functions return the netent structure, or a NULL pointer if an error occurs or the end of the file is reached.

/etc/networks
networks database file

4.3BSD, POSIX.1-2001.

getprotoent(3), getservent(3), networks(5)
RFC 1101

1993-05-15 BSD

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