Chapter 12 Identifying Local Interface Names and Indexes

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The IPv6 sockets API uses an interface index (a small positive integer) to identify the local interface joined to a multicast group. Interfaces are normally known by names such as "lan0”. On HP-UX implementations, when the system configures an interface, the kernel assigns a unique positive integer value (called the interface index) to that interface. These small positive integers start at one. Interface numbering is not necessarily contiguous.

This API defines:

two functions that map between an interface name and index:
- if_nametoindex()
- if_indextoname()
a function that returns all interface names and indexes:
- if_nameindex()
a function to return the dynamic memory allocated by the previous function:
- if_freenameindex()

Chapter 12 Identifying Local Interface Names and Indexes

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