if_nametoindex(3SOCKET) 				     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 interface 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 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 specified 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_namein-
			     dex 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 dynamically. 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().

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      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							    28 Jan 2009 					   if_nametoindex(3SOCKET)