IF_NAMETOINDEX(3) | Library Functions Manual | IF_NAMETOINDEX(3) |
if_nametoindex
, if_indextoname
,
if_nameindex
, if_freenameindex
—
#include <net/if.h>
unsigned int
if_nametoindex
(const
char *ifname);
char *
if_indextoname
(unsigned
int ifindex, char
*ifname);
struct if_nameindex *
if_nameindex
(void);
void
if_freenameindex
(struct
if_nameindex *ptr);
if_nametoindex
() function maps the interface name
specified in ifname to its corresponding index. If the
specified interface does not exist, it returns 0.
The if_indextoname
() function maps the
interface index specified in ifindex to it
corresponding name, which is copied into the buffer pointed to by
ifname, which must be of at least IFNAMSIZ bytes. This
pointer is also the return value of the function. If there is no interface
corresponding to the specified index, NULL is returned.
The if_nameindex
() function returns an
array of if_nameindex
structures, one structure per
interface, as defined in the include file
<net/if.h>
. The
if_nameindex
structure contains at least the
following entries:
unsigned int if_index; /* 1, 2, ... */ char *if_name; /* null terminated name: "le0", ... */
The end of the array of structures is indicated by a structure
with an if_index
of 0 and an
if_name
of NULL. A NULL pointer is returned upon an
error.
The if_freenameindex
() function frees the
dynamic memory that was allocated by
if_nameindex
().
if_nametoindex
() returns the
index number of the interface. If the interface is not found, a value of 0 is
returned and errno is set to
ENXIO
. A value of 0 is also returned if an error
occurs while retrieving the list of interfaces via
getifaddrs(3).
Upon successful completion,
if_indextoname
() returns
ifname. If the interface is not found, a NULL pointer
is returned and errno is set to
ENXIO
. A NULL pointer is also returned if an error
occurs while retrieving the list of interfaces via
getifaddrs(3).
The if_nameindex
() returns a NULL pointer
if an error occurs while retrieving the list of interfaces via
getifaddrs(3), or if
sufficient memory cannot be allocated.
if_nametoindex
(),
if_indextoname
(),
if_nameindex
(), and
if_freenameindex
() functions conform to
IEEE Std 1003.1-2001 (“POSIX.1”),
X/Open Networking Services Issue 5.2
(“XNS5.2”), and RFC 3493.
March 11, 2005 | NetBSD 9.2 |