zcl函数在zcl文档里的说明的疑问（求助TI工程师）

/*********************************************************************
 * @fn      zclClosures_RegisterDoorLockCmdCallbacks
 *
 * @brief   Register an applications DoorLock command callbacks
 *
 * @param   endpoint - application's endpoint
 * @param   callbacks - pointer to the callback record.
 *
 * @return  ZMemError if not able to allocate
 */
ZStatus_t zclClosures_RegisterDoorLockCmdCallbacks( uint8 endpoint, zclClosures_DoorLockAppCallbacks_t *callbacks )
{
  zclClosuresDoorLockCBRec_t *pNewItem;
  zclClosuresDoorLockCBRec_t *pLoop;

  // Register as a ZCL Plugin
  if ( !zclDoorLockPluginRegisted )
  {
    zcl_registerPlugin( ZCL_CLUSTER_ID_CLOSURES_DOOR_LOCK,
                        ZCL_CLUSTER_ID_CLOSURES_DOOR_LOCK,
                        zclClosures_HdlIncoming );
    zclDoorLockPluginRegisted = TRUE;
  }

  // Fill in the new profile list
  pNewItem = zcl_mem_alloc( sizeof( zclClosuresDoorLockCBRec_t ) );
  if ( pNewItem == NULL )
  {
    return ( ZMemError );
  }

  pNewItem->next = (zclClosuresDoorLockCBRec_t *)NULL;
  pNewItem->endpoint = endpoint;
  pNewItem->CBs = callbacks;

  // Find spot in list
  if ( zclClosuresDoorLockCBs == NULL )
  {
    zclClosuresDoorLockCBs = pNewItem;
  }
  else
  {
    // Look for end of list
    pLoop = zclClosuresDoorLockCBs;
    while ( pLoop->next != NULL )
    {
      pLoop = pLoop->next;
    }

    // Put new item at end of list
    pLoop->next = pNewItem;
  }
  return ( ZSuccess );
}