if_indextoname man page


This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

if_indextoname — map a network interface index to its corresponding name


#include <net/if.h>

char *if_indextoname(unsigned ifindex, char *ifname);


The if_indextoname() function shall map an interface index to its corresponding name.

When this function is called, ifname shall point to a buffer of at least {IF_NAMESIZE} bytes. The function shall place in this buffer the name of the interface with index ifindex.

Return Value

If ifindex is an interface index, then the function shall return the value supplied in ifname, which points to a buffer now containing the interface name. Otherwise, the function shall return a null pointer and set errno to indicate the error.


The if_indextoname() function shall fail if:

The interface does not exist.

The following sections are informative.

See Also

getsockopt(), if_freenameindex(), if_nameindex(), if_nametoindex(), setsockopt()

The Base Definitions volume of POSIX.1‐2008, <net_if.h>


2013 IEEE/The Open Group POSIX Programmer's Manual