ReleaseDeviceRequested

当另一个客户端尝试声明设备时，会发生此事件。 此事件的数据缓冲区如下所示。

Syntax

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

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

下表显示了此事件的数据缓冲区的内存布局。

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

Remarks

此事件由服务类扩展点（PosCx）代表设备驱动程序进行处理。 当客户端尝试声明另一个客户端正在使用的设备时，PosCx 在客户端中引发此事件，该客户端当前在扫描程序设备上具有声明，以指示另一个客户端正在尝试声明设备。 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