How to get the multiple selected item text from PtList

I am working under QNX4.25. I have several question about PtList
widget.

  1. How to get the multiple selected item text from PtList?

2.How to use the resources Pt_ARG_SELECTION_INDEXES ?

3.How to resize a PtList widget when the program is running ?

please give me examples.Thank you very much!