Sockets Library Functions                 if_nametoindex(3SOCKET)



NAME
     if_nametoindex,        if_indextoname,         if_nameindex,
     if_freenameindex - routines to map Internet Protocol network
     interface names and interface indexes

SYNOPSIS
     cc [ flag... ] file... -lsocket [ library... ]
     #include <net/if.h>

     unsigned int if_nametoindex(const char *ifname);


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


     struct if_nameindex *if_nameindex(void)


     void if_freenameindex(struct if_nameindex *ptr);


PARAMETERS
     ifname     interface name


     ifindex    interface index


     ptr        pointer returned by if_nameindex()


DESCRIPTION
     This API defines two functions that map between an  Internet
     Protocol  network interface name and index, a third function
     that returns all the interface  names  and  indexes,  and  a
     fourth  function  to  return the dynamic memory allocated by
     the previous function.


     Network interfaces are normally known by names such as eri0,
     sl1,  ppp2, and the like.  The ifname argument must point to
     a buffer of at least IF_NAMESIZE bytes into which the inter-
     face  name corresponding to the specified index is returned.
     IF_NAMESIZE is defined in <net/if.h> and its value  includes
     a terminating null byte at the end of the interface name.

     if_nametoindex()      The if_nametoindex() function  returns
                           the  interface  index corresponding to
                           the interface name pointed to  by  the
                           ifname   pointer.   If  the  specified
                           interface name  does  not  exist,  the
                           return value is 0, and errno is set to



SunOS 5.11          Last change: 12 Dec 2003                    1






Sockets Library Functions                 if_nametoindex(3SOCKET)



                           ENXIO. If there was  a  system  error,
                           such  as  running  out  of memory, the
                           return value is 0 and errno is set  to
                           the proper value, for example, ENOMEM.


     if_indextoname()      The if_indextoname() function maps  an
                           interface index into its corresponding
                           name. This pointer is also the  return
                           value of the function.  If there is no
                           interface corresponding to the  speci-
                           fied  index,  NULL  is  returned,  and
                           errno is set to ENXIO, if there was  a
                           system  error,  such as running out of
                           memory, if_indextoname() returns  NULL
                           and  errno  would be set to the proper
                           value, for example, ENOMEM.

 
     if_nameindex()        The if_nameindex() function returns an
                           array  of if_nameindex structures, one
                           structure    per    interface.     The
                           if_nameindex   structure   holds   the
                           information about a  single  interface
                           and  is  defined  when  the <net/if.h>
                           header is included:

                             struct if_nameindex
                               unsigned int   if_index; /* 1, 2, ... */
                               char          *if_name;  /* "net0", ... */
                             };

                           While   any   IPMP IP  interfaces  are
                           returned  by    *if_nameindex()*,  the
                           underlying IP interfaces that comprise
                           each IPMP group are not returned.

                           The end of the array of structures  is
                           indicated   by  a  structure  with  an
                           if_index of 0 and an if_name of  NULL.
                           The  function  returns  a null pointer
                           upon an error and sets  errno  to  the
                           appropriate value. The memory used for
                           this array of  structures  along  with
                           the  interface names pointed to by the
                           if_name members  is  obtained  dynami-
                           cally.  This  memory  is  freed by the
                           if_freenameindex() function.


     if_freenameindex()    The if_freenameindex() function  frees
                           the  dynamic memory that was allocated
                           by  if_nameindex().  The  argument  to
                           this  function  must be a pointer that
                           was returned by if_nameindex().





SunOS 5.11          Last change: 12 Dec 2003                    2






Sockets Library Functions                 if_nametoindex(3SOCKET)



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsl (32-bit)            |
    |                             | SUNWcslx (64-bit)           |
    |_____________________________|_____________________________|
    | MT Level                    | MT Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     ifconfig(1M), if_nametoindex(3XNET), attributes(5), if(7P)





































SunOS 5.11          Last change: 12 Dec 2003                    3