Iterate Over A Tree Of Features

It's also possible to iterate over all the features offered by a device or a subtree of this. To see how this is done, please have a look at the description of the function OBJ_GetFirstSibling().

To access e.g. the device information related features, the DMR_FindList() function must be called in a certain way:

//-----------------------------------------------------------------------------
// This function will try to obtain the handle to a certain driver feature list
HOBJ getDriverList( HDRV hDrv, const char* pName, const char* pAddListName, TDMR_ListType type )
//-----------------------------------------------------------------------------
{
  TPROPHANDLING_ERROR objResult;
  TDMR_ERROR dmrResult;
  HOBJ hObj = INVALID_ID;
  HLIST baseList;
 
  // try to locate the base list for these property
  if( ( dmrResult = DMR_FindList( hDrv, pAddListName, type, 0, &baseList ) ) == DMR_NO_ERROR )
  {
    // try to locate the property
    if( ( objResult = OBJ_GetHandleEx( baseList, pName, &hObj, smIgnoreProperties | smIgnoreMethods, 0 ) ) != PROPHANDLING_NO_ERROR )
    {
      printf( "OBJ_GetHandle for %s failed: %d Handle: %d. This list might not be supported by this device\n", pName, objResult, hObj );
    }
  }
  else
  {
    printf( "DMR_FindList failed: %d. Lists of type %d are not available for this device\n", dmrResult, type );
  }
  return hObj;
}
 
//-----------------------------------------------------------------------------
HOBJ getInfoProp( HDRV hDrv, const char* pSettingName, const char* pPropName )
//-----------------------------------------------------------------------------
{
  // Here the 'dmltInfo' makes sure that only the properties belonging
  // to the device information related subtree of the drivers feature will be considered
  return getDriverProperty( hDrv, pPropName, pSettingName, dmltInfo );
}
 
//-----------------------------------------------------------------------------
void myFun()
//-----------------------------------------------------------------------------
{
  HDRV hDrv = getTheDriverHandleFromSomewhere();
  HOBJ hProp = getInfoProp( hDrv, "DeviceInformation", "DeviceVersion" );
  // now the property is ready to use when available:
  if( hProp != INVALID_ID )
  {
    // do what needs to be done with the property
  }
  else
  {
    // oops... The feature is not offered by this device
  }
}