---
title: FSRef
framework: Core Services
role: symbol
role_heading: Structure
platforms: [Mac Catalyst 17.0+, macOS 10.0+]
path: coreservices/fsref
---

# FSRef

Identifies a directory or file, including a volume’s root directory.

## Declaration

```occ
typedef struct FSRef {
    ...
} FSRef;
```

## Overview

> **important:** `FSRef` structures are designed to work with 32-bit inode numbers. Because APFS uses 64-bit inode numbers, interacting with APIs that return an `FSRef` value or that take one or more `FSRef` values as an argument may result in performance issues in APFS.

This data type’s purpose is similar to an [FSSpec](fsspec.md) except that an `FSRef` is completely opaque. An `FSRef` contains whatever information is needed to find the given object; the internal structure of an `FSRef` is likely to vary based on the volume format, and may vary based on the particular object being identified.

The client of the File Manager cannot examine the contents of an `FSRef` to extract information about the parent directory or the object’s name. Similarly, an `FSRef` cannot be constructed directly by the client; the `FSRef` must be constructed and returned via the File Manager. There is no need to call the File Manager to dispose an `FSRef`.

To determine the volume, parent directory and name associated with an `FSRef`, or to get an equivalent `FSSpec`, use the [FSGetCatalogInfo](1565356-fsgetcataloginfo.md) call.

## Topics

### Instance Properties

- [hidden](fsref/1565674-hidden.md)