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33 .\" From: @(#)rcmd.3 8.1 (Berkeley) 6/4/93
43 .Nd convert interface index to name, and vice versa
45 .Fd #include <net/if.h>
47 .Fn if_nametoindex "const char *ifname"
49 .Fn if_indextoname "unsigned int ifindex" "char *ifname"
50 .Ft "struct if_nameindex *"
51 .Fn if_nameindex "void"
53 .Fn if_freenameindex "struct if_nameindex *ptr"
55 These functions map interface indexes to interface names (such as
61 function converts an interface name specified by the
63 argument to an interface index (positive integer value).
64 If the specified interface does not exist, 0 will be returned.
67 converts an interface index specified by the
69 argument to an interface name.
72 argument must point to a buffer of at least
74 bytes into which the interface name corresponding to the specified index is
79 and its value includes a terminating null byte at the end of the
81 This pointer is also the return value of the function.
82 If there is no interface corresponding to the specified index,
96 unsigned int if_index; /* 1, 2, ... */
97 char *if_name; /* null terminated name: "le0", ... */
101 The end of the array of structures is indicated by a structure with
108 The function returns a null pointer on error.
109 The memory used for this array of structures along with the interface
110 names pointed to by the
112 members is obtained dynamically.
113 This memory is freed by the
118 takes a pointer that was returned by
122 and it reclaims the region allocated.
125 returns 0 on error, positive integer on success.
133 R. Gilligan, S. Thomson, J. Bound, and W. Stevens,
134 ``Basic Socket Interface Extensions for IPv6,'' RFC2553, March 1999.
136 These functions are defined in ``Basic Socket Interface Extensions for IPv6''