# FS_GetOverlayFileID

## C Specification

  `#include <nitro/fs.h>`
  `FSFileID FS_GetOverlayFileID(const FSOverlayInfo *p_ovi);`

## Arguments

p_ovi | `FSOverlayInfo` structure that holds overlay module information.

## Return Values

Returns the ID of the file in which the image of the overlay module is stored.

## Description

This function acquires the ID of the file in which the image of the overlay module has been stored. `FS_LoadOverlayInfo` loads the image from this file internally. Note that the file that is opened using the ID that this function returns is not in the directory hierarchy. Therefore, a failure will occur when the `FS_GetPathName` function is called for this file.
It is possible to load overlays asynchronously by loading the file using the file ID returned by this function after using `FS_ClearOverlayImage` to initialize the address returned by `FS_GetOverlayAddress`.

## See Also

``FSOverlayInfo`, `FS_LoadOverlayInfo`, `FS_GetOverlayAddress`, `FS_LoadOverlayImage`, FS_StartOverlay`

## Revision History

11/17/2004 Revisions due to the elimination of the FS_RegisterOverlayToDebugge function.
10/19/2004 Added description regarding the `FS_RegisterOverlayToDebugger` function.
06/11/2004 Initial version.