In this contest, index refers to the index(3) function. In this case it
doesn't really harm, as this function is never called with idx == NULL.
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation (the SNMPv3 bits), Google Summer of Code 2005
Reviewed by: philip@ (mostly), bz@ (earlier version based on p4 ch124545)
Approved by: philip@