trusty (3) if_nametoindex.3.gz

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NAME
       if_nametoindex, if_indextoname - mappings between network interface names and indexes


SYNOPSIS
       #include <net/if.h>

       unsigned int if_nametoindex(const char *ifname);

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


DESCRIPTION
       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.


RETURN VALUE
       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.


ERRORS
       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).


CONFORMING TO
       RFC 3493, POSIX.1-2001.

       This function first appeared in BSDi.


SEE ALSO
       getifaddrs(3), if_nameindex(3), ifconfig(8)


COLOPHON
       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.