if_nametoindex(3) — Linux manual page


if_nametoindex(3)       Library Functions Manual       if_nametoindex(3)

NAME         top

       if_nametoindex, if_indextoname - mappings between network
       interface names and indexes

LIBRARY         top

       Standard C library (libc, -lc)

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 to
       indicate the error.

       On success, if_indextoname() returns ifname; on error, NULL is
       returned and errno is set to indicate the error.

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 │

STANDARDS         top

       POSIX.1-2008, RFC 3493.

HISTORY         top

       POSIX.1-2001.  BSDi.

SEE ALSO         top

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

Linux man-pages (unreleased)     (date)                if_nametoindex(3)

Pages that refer to this page: if_nameindex(3)