You can get Persistent Name on several entities using

// Get Dtk_InfoPtr class 
Dtk_InfoPtr infos = inObject->GetInfos();
// Get Persistent Name 
Dtk_string name = infos->GetPersistentName();

Here are the supported Persistent Name following different readers

The intention of persistent name is to give the same identifier for a same prototype, face or edge between

different versions of a file if the geometry is not affected by the change
different versions of a Datakit API on a same file (except if we solve an issue)
prototypes representing the same file

PesistentName are computed using information in binary file for CatiaV5, CatiaV6, Solidworks, SolidEdge, NX and Creo readers