[GENERAL] What is the correct way to get the content of a varchar field in pgsql's source code

[Felix . 徐]

Hi all,
I've learnt from the source code to open a table and scan it, like this:

Relation qma = try_relation_open(qmappersta, AccessShareLock);
  if(qma!=NULL){
    HeapScanDesc scan= heap_beginscan(qma,SnapshotNow,0,NULL);
  HeapTuple tup;
TupleDesc tupDesc= RelationGetDescr(qma);
    Datum   *values;
  bool *nulls;
    int value1;
    char value2;
    while ((tup = heap_getnext(scan, ForwardScanDirection)) != NULL){
        heap_deform_tuple(tup,tupDesc,values, nulls);
        /* int values can be retrieved easily */
        value1=values[0];
        /* how to retrieve the content of a varchar field here? */
        /* What I've tried: */
        value2=VARDATA_ANY(values[2]);
        /* But value2 seems to be incorrect
           if the original data is "abcd", then I will get "abcd2" here(in
most cases, a "2" is appended to the data...), I'm wondering  how to get
the data properly...
           I've also tried VARDATA macro and encountered with the same
problem.
        */
    }
  }

Thanks!