Compartir a través de

IDeviceSpecificProperty::GetValue

  • Artículo
Previous Next

IDeviceSpecificProperty::GetValue

The GetValue method gets the current value of the device-specific property.

HRESULT GetValue(
  void  *pvValue,
  DWORD  *pcbValue
);

Parameters

pvValue

[out]  Pointer to a caller-allocated buffer into which the method writes the property value.

pcbValue

[inout]  Pointer to a DWORD variable that specifies the size in bytes of the property value. On entry, *pcbValue contains the size of the caller-allocated buffer (or 0 if pvValue is NULL). Before returning, the method writes the actual size of the property value written to the buffer (or the required size if the buffer is too small or if pvValue is NULL).

Return Value

If the method succeeds, it returns S_OK. If it fails, possible return codes include, but are not limited to, the values shown in the following table.

Return code Description
E_POINTER Pointer pcbValue is NULL.
HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER) The buffer pointed to by parameter pvValue is too small to contain the property value, or pvValue is NULL and the size of the property value is fixed rather than variable.

For information about the HRESULT_FROM_WIN32 macro, see the Windows SDK documentation.

Remarks

If the size of the property value is variable rather than fixed, the caller can obtain the required buffer size by calling GetValue with parameter pvValue = NULL and *pcbValue = 0. The method writes the required buffer size to *pcbValue. With this information, the caller can allocate a buffer of the required size and call GetValue a second time to obtain the property value.

If the caller-allocated buffer is too small to hold the property value, GetValue writes the required buffer size to *pcbValue and returns an error status code. In this case, it writes nothing to the buffer pointed by pvValue.

Requirements

Client: Windows Vista

Header: Include Devicetopology.h.

See Also

Previous Next