opensetGenerally when an IO space is opened with open it won’t
automatically become the current IO space; it will only happens if
there wasn’t an IO space previously open.
The standard function openset is like open that always
sets the opened IO space as the new current space. It has the
following prototype:
fun openset = (string handler, uint<64> flags = 0) int<32>
Where the meaning of handler, flags and the returned value
are exactly like in open.