GETNETENT

Section: Linux Programmer's Manual (3)
Updated: 2008-08-19
Index Return to Main Contents
 

NAME

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

SYNOPSIS

#include <netdb.h>

struct netent *getnetent(void);

struct netent *getnetbyname(const char *name);

struct netent *getnetbyaddr(uint32_t net, int type);

void setnetent(int stayopen);

void endnetent(void);
 

DESCRIPTION

The getnetent() function reads the next entry from the networks database and returns a netent structure containing the broken-out fields from the entry. A connection is opened to the database if necessary.

The getnetbyname() function returns a netent structure for the entry from the database that matches the network name.

The getnetbyaddr() function returns a netent structure for the entry from the database that matches the network number net of type type. The net argument must be in host byte order.

The setnetent() function opens a connection to the database, and sets the next entry to the first entry. If stayopen is non-zero, then the connection to the database will not be closed between calls to one of the getnet*() functions.

The endnetent() function closes the connection to the database.

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 */
    uint32_t   n_net;      /* network number */
}

The members of the netent structure are:

n_name
The official name of the network.
n_aliases
A NULL-terminated list of alternative names for the network.
n_addrtype
The type of the network number; always AF_INET.
n_net
The network number in host byte order.
 

RETURN VALUE

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

FILES

/etc/networks
networks database file
 

CONFORMING TO

4.3BSD, POSIX.1-2001.  

NOTES

In glibc versions before 2.2, the net argument of getnetbyaddr() was of type long.  

SEE ALSO

getnetent_r(3), getprotoent(3), getservent(3)
RFC 1101  

COLOPHON

This page is part of release 3.22 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.