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

# HDF_SD_START

The HDF_SD_START function opens or creates an HDF file and initializes the SD interface.

Note that every file opened with HDF_SD_START should eventually be closed with a call to HDF_SD_END.

## Examples

; Open a new HDF file. The file is ready to be accessed:

SDinterface_id = HDF_SD_START('test.hdf', /CREATE)

; When finished with the file, close it with a call to HDF_SD_END:

HDF_SD_END, SDinterface_id

For a more complicated example, see the documentation for HDF_SD_ATTRSET.

## Syntax

Result = HDF_SD_START( Filename [, /READ | , /RDWR] [, /CREATE] )

## Return Value

The returned value of this function is the SD ID of the HDF file. If no keywords are present, the file is opened in read-only mode.

## Arguments

### Filename

A scalar string containing the name of the file to be opened or created. HDF_SD_START can open the following file types: XDR-based NetCDF files, “old-style” DFSD files, or “new-style” SD files. New files are created as “new-style” SD files.

## Keywords

### READ

Set this keyword to open the SD interface in read-only mode. If no keywords are specified, this is the default behavior.

### RDWR

Set this keyword to open the SD interface in read and write mode.

### CREATE

Set this keyword to create a new SD file.

## Version History

4.0 | Introduced

## See Also

HDF_CLOSE, HDF_OPEN, HDF_SD_ATTRFIND, HDF_SD_ATTRINFO, HDF_SD_ATTRSET, HDF_SD_CREATE, HDF_SD_END, HDF_SD_FILEINFO, HDF_SD_NAMETOINDEX, HDF_SD_REFTOINDEX, HDF_SD_SELECT, HDF_SD_SETEXTFILE