if_indextoname Subroutine
Purpose
Maps an interface index into its corresponding name.
Library
Standard C Library <libc.a>
Syntax
#include <net/if.h>
char *if_indextoname(unsigned int ifindex, char *ifname);Description
When the if_indextoname subroutine is called, the ifname parameter
points to a buffer of at least IF_NAMESIZE bytes. The if_indextoname subroutine
places the name of the interface in this buffer with the ifindex index.
Note: IF_NAMESIZE is also defined in <net/if.h> and its
value includes a terminating null byte at the end of the interface
name.
If ifindex is an interface index, the if_indextoname Subroutine returns the ifname value, which points to a buffer containing the interface name. Otherwise, it returns a NULL pointer and sets the errno global value to indicate the error.
If there is no interface corresponding to the specified index, the errno global value is set to ENXIO. If a system error occurs (such as insufficient memory), the errno global value is set to the proper value (such as, ENOMEM).
Parameters
| Item | Description |
|---|---|
| ifindex | Possible interface index |
| ifname | Possible name of an interface |
Error Codes
| Item | Description |
|---|---|
| ENXIO | There is no interface corresponding to the specified index |
| ENOMEM | Insufficient memory |