Device driver function 0Eh      Close Device            b   c

    Close Device informs the driver that a file device or character
    device is being closed.

    This function can be used for both block and character device
    drivers.

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    DOS calls this function only if bit 11 is set in the dhAttributes
    field of the DeviceHeader structure for the driver.

    DOS calls this function whenever an application closes a file or
    device. This function can be used in conjunction with Open Device
    (device driver function 0Dh) to manage internal buffers and device
    initialization.

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    ocrUnit
    Specifies the device on which the file is being closed. This field
    is used with block device drivers only.

    
    ocrStatus
    Specifies the status of the completed function. If the function
    was successful, the driver must set the done bit (bit 8).
    Otherwise, the driver must set both the error and done bits (bits
    15 and 8) and copy an error value to the low-order byte.