DispatchPnP
The DispatchPnP routine services IRPs containing the IRP_MJ_PNP I/O function code.
DRIVER_DISPATCH DispatchPnP;
NTSTATUS
DispatchPnP(
__in struct _DEVICE_OBJECT *DeviceObject,
__in struct _IRP *Irp
)
{...}
Parameters
- DeviceObject
- Caller-supplied pointer to a DEVICE_OBJECT structure. This is the device object for the target device, previously created by the driver's AddDevice routine.
- Irp
- Caller-supplied pointer to an IRP structure that describes the requested I/O operation.
Return Value
If the routine succeeds, it must return STATUS_SUCCESS. Otherwise, it must return one of the error status values defined in Ntstatus.h.
Comments
A driver's DispatchPnP routine should be named XxxDispatchPnP, where Xxx is a driver-specific prefix. The driver's DriverEntry routine must store the DispatchPnP routine's address in DriverObject->MajorFunction[IRP_MJ_PNP].
Input parameters for all Dispatch routines are supplied in the IRP structure pointed to by Irp. Additional parameters are supplied in the driver's associated I/O stack location, which is described by the IO_STACK_LOCATION structure and can be obtained by calling IoGetCurrentIrpStackLocation.
Generally, all Dispatch routines execute in an arbitrary thread context at IRQL = PASSIVE_LEVEL, but there are exceptions. For more information, see Dispatch Routines and IRQLs.
For more information about DispatchPnP routines, see Writing Dispatch Routines. For more information about IRPs, see Handling IRPs.
Example
To define a DispatchPnP callback function that is named MyDispatchPnP, you must first provide a function declaration that Static Driver Verifier (SDV) and other verification tools require, as follows:
DRIVER_DISPATCH MyDispatchPnP;
Then, implement your callback function as follows:
NTSTATUS
MyDispatchPnP(
__in struct _DEVICE_OBJECT *DeviceObject,
__in struct _IRP *Irp
)
{
// Function body
}
The DRIVER_DISPATCH function type is defined in the Wdm.h header file. For more information about SDV requirements for function declarations, see Declaring Functions Using Function Role Types for WDM Drivers.
Requirements
IRQL: PASSIVE_LEVEL (see Comments section)
Headers: Declared in Wdm.h. Include Wdm.h, Ntddk.h, or Ntifs.h.