if_nametoindex(3) — Linux manual page


IF_NAMETOINDEX(3)         Linux Programmer's Manual        IF_NAMETOINDEX(3)

NAME         top

       if_nametoindex,  if_indextoname  - mappings between network interface
       names and indexes

SYNOPSIS         top

       #include <net/if.h>

       unsigned int if_nametoindex(const char *ifname);

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

DESCRIPTION         top

       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         top

       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         top

       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).

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface                          Attribute     Value   │
       │if_nametoindex(), if_indextoname() │ Thread safety │ MT-Safe │

CONFORMING TO         top

       POSIX.1-2001, POSIX.1-2008, RFC 3493.

       This function first appeared in BSDi.

SEE ALSO         top

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

COLOPHON         top

       This page is part of release 5.08 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

GNU                              2017-09-15                IF_NAMETOINDEX(3)

Pages that refer to this page: if_freenameindex(3)if_nameindex(3)