The HDF_VD_GETNEXT function returns the reference number of the next object inside a VData in a Hierarchical Data Format file. If Id is -1, the first item in the VData is returned, otherwise Id should be set to a reference number previously returned by HDF_VD_GETNEXT. HDF_VD_GETNEXT returns -1 if there was an error or there are no more objects after the one specified by Id .

Calling Sequence

Result = HDF_VD_GETNEXT( VData, Id )



The VData handle returned by a previous call to HDF_VD_ATTACH.


A VGroup or VData reference number obtained by a previous call to HDF_VG_GETNEXT or HDF_VD_GETNEXT. Alternatively, this value can be set to -1 to return the first item in the VData.