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

# HDF_VD_ATTACH

The HDF_VD_ATTACH function accesses a VData with the given Idin an HDF file.

## Syntax

Result = HDF_VD_ATTACH( FileHandle, VData_id [, /READ] [, /WRITE] )

## Return Value

If successful, a handle for that VData is returned, otherwise 0 is returned.

## Arguments

### FileHandle

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

### VData_id

The VData reference number, usually obtained by HDF_VD_GETID or HDF_VD_LONE. Set this argument to -1 to create a new VData.

## Keywords

### READ

Set this keyword to open the VData for reading. This is the default.

### WRITE

Set this keyword to open the VData for writing. If VData_id is set equal to -1, the file is opened for writing whether or not this keyword is set.

## Version History

4.0 | Introduced

## See Also

HDF_VD_DETACH