INT 15 - OS HOOK - DEVICE CLOSE
AH = 81h
BX = device ID
CX = process ID
CF clear
Return: CF clear if successful
AH = 00h
CF set on error
AH = status (see AH=80h)
Note:   this function should be hooked by a multitasker which wishes to keep
track of device ownership; the default BIOS handler merely returns
successfully
SeeAlso: AH=82h

See also: 1580

1581 - OS HOOK - DEVICE CLOSE