MaxPacketSize Property

项目
09/21/2010

The MaxPacketSize property gets or sets the wMaxPacketSize field of the endpoint descriptor, as described in section 9.6.6 of the USB 2.0 specification.

This property is read/write.

Syntax

HRESULT put_MaxPacketSize(
  [in]           SHORT sMaxPacketSize
);

HRESULT get_MaxPacketSize(
  [out, retval]  SHORT *psMaxPacket
);

Property Value

The new maximum packet size for the endpoint.

Error Codes

MaxPacketSize returns S_OK if the operation succeeds or E_POINTER if the psMaxPacket parameter is not a valid pointer.

Remarks

The following C++ code example shows how to set and get the MaxPacketSize property.

HRESULT CLoopBackDevice::UpdateEndpointMaxPacketSize(ISoftUSBEndpoint *piEndpoint)
{
HRESULT hr = S_OK;
SHORT sMaxPacketSize = 0;
SHORT sNewMaxPacketSize = 1024;

 if(NULL == piEndpoint)
{
 hr = E_INVALIDARG;
 goto Exit;
}

// Get the current MaxPacketSize property
 hr = piEndpoint->get_MaxPacketSize (&sMaxPacketSize);
 if(FAILED(hr))
 goto Exit;

// Update the MaxPacketSize if required
 if (sNewMaxPacketSize != sMaxPacketSize)
{
 hr = piEndpoint->put_MaxPacketSize(sNewMaxPacketSize);
 if(FAILED(hr))
 goto Exit;
}
Exit:
 return hr;
}

Requirements

Header

SoftUSBif.h

通过