key

A string whose value names the key in
the system registry whose subkeys you want.

To uniquely identify a key, specify the list of parent keys
above it in the hierarchy, starting with the root key. The keys
in the list are separated by backslashes.

subkeys

An array variable of strings in which
you want to store the subkeys.

If the array is variable size, its upper bound will reflect
the number of subkeys found.

If the array is fixed size, it must be large enough to hold
all the subkeys. However, there will be no way to know how many subkeys
were actually found.