IWDFUsbTargetPipe::RetrievePipePolicy method

The RetrievePipePolicy method retrieves a WinUsb pipe policy.

Syntax


HRESULT RetrievePipePolicy(
  [in]       ULONG PolicyType,
  [in, out]  ULONG *ValueLength,
  [out]      PVOID Value
);

Parameters

PolicyType [in]: The type of WinUsb pipe policy that the UMDF driver requests.
ValueLength [in, out]: A pointer to a variable that, on input, contains the size, in bytes, of the buffer that RetrievePipePolicy supplies for Value. On output, this parameter contains the size that RetrievePipePolicy requires for Value.
Value [out]: A pointer that receives the buffer that contains the WinUsb pipe policy.

Return value

RetrievePipePolicy returns one of the following values:

Return code	Description
S_OK	RetrievePipePolicy successfully retrieved the WinUsb pipe policy.
E_OUTOFMEMORY	RetrievePipePolicy encountered an allocation failure.
An error code that is defined in Winerror.h	This value corresponds to the error code that the WinUsb API returned.

Remarks

Pipe policy controls the behavior of the USB pipe (for example, time-outs, handling short packets, and so on).

For more information about valid policy types that a UMDF driver can pass for the PolicyType parameter and values that the framework returns, see the WinUsb_GetPipePolicy function.

For information about the behavior of the pipe policies, see WinUSB Functions for Pipe Policy Modification.

The RetrievePipePolicy method generates a UMDF request and synchronously sends the request to the I/O target.

Requirements