User port driver

Because WPP tracing is enabled for your driver project, the PDB symbol file created during the build process contains trace message formatting instructions. If you configure the host and target computers for WPP tracing, your driver can send trace messages to a file or the debugger. You can use Tracepdb. The following command creates TMF files for the driver project. The -f option specifies the location and the name of the PDB symbol file.

The -p option specifies the location for the TMF files that are created by Tracepdb. For more information, see Tracepdb Commands. At the specified location you'll see three files one per. They are given GUID file names. The guid argument specifies the GUID of the trace provider, which is the client driver. As another option, you can type the following command and specify the GUID in a. The file contains the GUID in hyphen format:.

Verify that trace messages appear in the Debugger Immediate Window on the host computer. Skip to main content. This browser is no longer supported. Download Microsoft Edge More info. Contents Exit focus mode.

Please rate your experience Yes No. Any additional feedback? Submit and view feedback for This product This page. View all page feedback. In this article. Declares and defines a callback class that implements the IDriverEntry interface. The class defines methods that are invoked by the framework driver object. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.

Feedback will be sent to Microsoft: By pressing the submit button, your feedback will be used to improve Microsoft products and services. Privacy policy. For most devices, the Ports device setup class and the Serial function driver provide the functionality required to operate serial ports and COM ports.

To install serial ports and COM ports using these system-supplied components, do the following:. The remaining elements of the MajorFunction array hold pointers to the default dispatch function nt! In the debugger output, you can see that the parport driver provided function pointers for Unload and AddDevice , but did not provide a function pointer for StartIo.

The following diagram illustrates the function pointers that the parport driver provided in its DriverEntry function. The function pointers provided by parport are shaded. Over a period of time, as driver developers inside and outside of Microsoft gained experience with the Windows Driver Model WDM , they realized a couple of things about dispatch functions:. To make things easier for driver developers, Microsoft created several technology-specific driver models.

At first glance, the technology-specific models seem quite different from each other, but a closer look reveals that many of them are based on this paradigm:. Proseware and Contoso can each write small drivers that handle the requirements of their specific robots. For example, Proseware could write ProsewareRobot.

Likewise, the pair of drivers ContosoRobot. In its most general form, the idea is that you can create drivers by using specific. In a specific. The DriverEntry function of specific. Normally you would expect DriverEntry to fill in several elements of the MajorFunction array with pointers to dispatch functions. However, in a driver pair model, DriverEntry does not necessarily do this. Instead the DriverEntry function of specific. The following code example shows how the initialization function might be called in the ProsewareRobot.

The initialization function in GeneralRobot. If GeneralRobot. At some point after DriverEntry returns, a device stack gets constructed for the Proseware Robot device node.

The device stack might look like this. As shown in the preceding diagram, the device stack for Proseware Robot has three device objects.