This code creates a new exception object in the class user_exception_pspp, invokes its SetMessage function, and throws the exception:

pbclass cls;
pbmethodID mid;
pbobject ex;
pbgroup group;
PBCallInfo* ci = new PBCallInfo;
 
//  Throw exception 
group = session-> FindGroup("user_exception_pspp",
   pbgroup_userobject);
if (group==NULL) 
   return;
cls = session->FindClass(group, "user_exception_pspp");
if (group==NULL) 
   return;
ex = session -> NewObject(cls);
mid = session-> GetMethodID(cls,
   "setmessage", PBRT_FUNCTION, "QS");
session-> InitCallInfo(cls,mid,ci);
 
ci-> pArgs[0].SetPBString(session, "Test exception");
 
session -> InvokeObjectFunction(ex,mid,ci);
session -> ThrowException(ex);
if (!ThrowToPB)
   session -> ClearException();
session -> FreeCallInfo(ci);
delete ci;
return;