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

# HDF_GR_START

This function initializes the HDF GR interface for the specified file. This function is used with the HDF_GR_END procedure to define the extent of the HDF GR interface session. As with the start routines in the other interfaces, HDF_GR_START initializes the internal interface structures needed for the remaining HDF_GR_ routines. Use the general purpose routines HDF_OPEN and HDF_CLOSE to manage file access. The HDF_GR_ routines will not open and close HDF files.

Note: Failure to use HDF_CLOSE properly may result in lost data or corrupted HDF files.

## Syntax

Result = HDF_GR_START(file_id)

## Return Value

Returns the HDF GR interface identifier if successful or FAIL (-1) otherwise.

## Arguments

### file_id

File identifier returned by HDF_OPEN.

## Keywords

None

## Version History

5.2 | Introduced