IQueueCallbackWrite interface (wudfddi.h)

[Warning: UMDF 2 is the latest version of UMDF and supersedes UMDF 1. All new UMDF drivers should be written using UMDF 2. No new features are being added to UMDF 1 and there is limited support for UMDF 1 on newer versions of Windows 10. Universal Windows drivers must use UMDF 2. For more info, see Getting Started with UMDF.]

An I/O queue object notifies a driver when a write request is available for the driver. The I/O queue object notifies the driver when an application calls the Microsoft Win32 WriteFile or WriteFileEx function. The driver can handle the notification by registering the IQueueCallbackWrite interface.


The IQueueCallbackWrite interface inherits from the IUnknown interface. IQueueCallbackWrite also has these types of members:

  • Methods


The IQueueCallbackWrite interface has these methods.


The OnWrite method is called to handle a write request when an application writes information to a device through the Microsoft Win32 WriteFile or WriteFileEx function.


A driver registers the IQueueCallbackWrite interface when it calls the IWDFDevice::CreateIoQueue method to create an I/O queue or to configure the default I/O queue. For more information about creating or configuring I/O queues, see Configuring Dispatch Mode for an I/O Queue.


Target Platform Windows
Header wudfddi.h