mio_select_pool

	status.i4.v = mio_select_pool(pool_id.i4.v)

	This routine selects which MIO pool of data to use with subsequent
	use of MIO.  This routine is only needed by a complex application
	that is using mulitple data-set representations of simulated data.
	A previous call to dio_simulate is required.

	pool_id		an integer value to identify an unique MIO pool
			(The default "pool_id" (the one used if
			 'mio_select_pool' is never called) is 0.)

	This function returns ACNET status values as follows:

	negative value		ACNET error
	positive value		success: returns previously selected pool_id

	This function requires the following include files:

	diolib_h, acnet_errors_h

	Related functions:

	dio_simulate, mio_read, mio_set, mio_control, mio_cancel,
	mio_fill_status

	C/C++ usage:

	int	status;
	int	pool_id = 1;

	status = mio_select_pool(pool_id);