NAME
	CloseDevice -- conclude access to a device

   SYNOPSIS
	CloseDevice(iORequest)
		    A1

	void CloseDevice(struct IORequest *);

   FUNCTION
	This function informs the device that access to a device/unit
	previously opened has been concluded.  The device may perform
	certain house-cleaning operations.

	The user must ensure that all outstanding IORequests have been
	returned before closing the device.  The AbortIO function can kill
	any stragglers.

	After a close, the I/O request structure is free to be reused.
	Starting with V36 exec it is safe to CloseDevice() with an
	IORequest that is either cleared to zeros, or failed to
	open.

   INPUTS
	iORequest - pointer to an I/O request structure

   SEE ALSO
	OpenDevice()