IF_NAMETOINDEX(3) | Library Functions Manual | IF_NAMETOINDEX(3) |
if_nametoindex
,
if_indextoname
,
if_nameindex
,
if_freenameindex
— provide
mappings between interface names and indexes
#include
<sys/types.h>
#include <sys/socket.h>
#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);
The
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
().
Upon successful completion,
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.
The if_nametoindex
(),
if_indextoname
(),
if_nameindex
(), and
if_freenameindex
() functions conform to
RFC 2553.
The implementation first appeared in BSDi BSD/OS.
November 23, 2005 | macOS 14.6 |