ReleaseDeviceRequested

This event occurs when another client attempts to claim a device. The data buffer for this event is as follows.

Syntax

typedef struct _PosEventDataHeader
{
    // Event enumeration value
    PosEventType EventType;

    // Size of buffer required to read entire event (including header)
    UINT32 DataLength;
} PosEventDataHeader;

The following table shows the memory layout of the data buffer for this event.

Memory value	Description
0x00000001	EventType = PosEventType::ReleaseDeviceRequested
0x00000008	sizeof(PosEventDataHeader)

 

Remarks

This event is handled on behalf of the device driver by Point of Service Class Extension (PosCx). When a client attempts to claim a device that another client is using, PosCx raises this event in the client that currently has a claim on the scanner device to indicate that another client is attempting to claim the device. The current client is expected to either retain its claim (IOCTL_POINT_OF_SERVICE_RETAIN_DEVICE) or release its claim (IOCTL_POINT_OF_SERVICE_RELEASE_DEVICE) of the device in response to this event. If the current client does not retain its claim on the device, its ClaimedBarcodeScanner object will no longer be valid.

Requirements

Header: pointofservicedriverinterface.h

 

 

Send comments about this topic to Microsoft