Routines (alphabetical) > Routines: H > HDF Routines > HDF_VD_GETID

# HDF_VD_GETID

The HDF_VD_GETID function returns the VData reference number for the next VData in an HDF file after the specified VData_id.

Set VData_id to -1 to return the first VData ID in the file.

## Syntax

Result = HDF_VD_GETID(FileHandle, VData_id)

## Return Value

Returns the next VData reference number.

## Arguments

### FileHandle

The HDF file handle returned by a previous call to HDF_OPEN.

### VData_id

The VData reference number, generally obtained by HDF_VD_GETID or HDF_VD_LONE. Set this argument to -1 to return the first VData in the file.

## Keywords

None

## Version History

4.0 | Introduced