if_nametoindex, if_indextoname - mappings between network interface names and
indexes
#include <net/if.h>
unsigned int if_nametoindex(const char *ifname);
char *if_indextoname(unsigned int ifindex, char *ifname);
The
if_nametoindex() function returns the index of the network interface
corresponding to the name
ifname.
The
if_indextoname() function returns the name of the network interface
corresponding to the interface index
ifindex. The name is placed in the
buffer pointed to by
ifname. The buffer must allow for the storage of
at least
IF_NAMESIZE bytes.
On success,
if_nametoindex() returns the index number of the network
interface; on error, 0 is returned and
errno is set appropriately.
On success,
if_indextoname() returns
ifname; on error, NULL is
returned and
errno is set appropriately.
if_nametoindex() may fail and set
errno if:
- ENODEV
- No interface found with given name.
if_indextoname() may fail and set
errno if:
- ENXIO
- No interface found for the index.
if_nametoindex() and
if_indextoname() may also fail for any of the
errors specified for
socket(2) or
ioctl(2).
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| if_nametoindex (), if_indextoname () |
Thread safety |
MT-Safe |
POSIX.1-2001, POSIX.1-2008, RFC 3493.
This function first appeared in BSDi.
getifaddrs(3),
if_nameindex(3),
ifconfig(8)