---
title: fileIdentifier
framework: coregraphics
role: symbol
role_heading: Instance Property
path: coregraphics/cgpdfdocument/fileidentifier
---

# fileIdentifier

Gets the file identifier for a PDF document.

## Declaration

```swift
var fileIdentifier: CGPDFArrayRef? { get }
```

## Discussion

Discussion A PDF file identifier is defined in the PDF specification as an array of two strings, the first of which is a permanent identifier that doesn’t change even when the file is updated. The second string changes each time the file is updated. For more information, see PDF Reference: Version 1.3 (Second Edition), Adobe Systems Incorporated.

## See Also

### Examining a PDF Document

- [catalog](coregraphics/cgpdfdocument/catalog.md)
- [info](coregraphics/cgpdfdocument/info.md)
- [numberOfPages](coregraphics/cgpdfdocument/numberofpages.md)
- [getVersion(majorVersion:minorVersion:)](coregraphics/cgpdfdocument/getversion(majorversion:minorversion:).md)
- [page(at:)](coregraphics/cgpdfdocument/page(at:).md)