Address testing macros

The macros listed in Table 1 can be used to test for special IPv6 addresses.

Table 1. Address testing macros
Macros	Assembler Callable services	C/C++ using Language Environment®	IP CICS® C sockets	REXX	Socket Extended macro/call (includes CICS EZASOKET)
IN6_IS_ADDR_UNSPECIFIED	No	Yes	Yes	No	No
IN6_IS_ADDR_LOOPBACK	No	Yes	Yes	No	No
IN6_IS_ADDR_MULTICAST	No	Yes	Yes	No	No
IN6_IS_ADDR_LINKLOCAL	No	Yes	Yes	No	No
IN6_IS_ADDR_V4MAPPED	No	Yes	Yes	No	No
IN6_IS_ADDR_V4COMPAT	No	Yes	Yes	No	No
IN6_IS_ADDR_MC_NODELOCAL	No	Yes	Yes	No	No
IN6_IS_ADDR_MC_LINKLOCAL	No	Yes	Yes	No	No
IN6_IS_ADDR_MC_SITELOCAL	No	Yes	Yes	No	No
IN6_IS_ADDR_MC_ORGLOCAL	No	Yes	Yes	No	No
IN6_IS_ADDR_MC_GLOBAL	No	Yes	Yes	No	No

The macros function in the following ways:

The first six macros return true if the address is of the specified type, or false otherwise.
The last five macros test the scope of a multicast address and return true if the address is a multicast address of the specified scope, or false if the address is either not a multicast address or not of the specified scope.
IN6_IS_ADDR_LINKLOCAL returns true only for IPv6 link-local unicast addresses, and therefore the IN6_IS_ADDR_LINKLOCAL macro returns false for the IPv6 loopback address (::1). This macro does not return true for IPv6 multicast addresses of link-local scope.