---
title: UCKeySequenceDataIndex
framework: coreservices
role: symbol
role_heading: Structure
path: coreservices/uckeysequencedataindex
---

# UCKeySequenceDataIndex

Contains offsets to a list of character sequences for a 'uchr' resource.

## Declaration

```swift
struct UCKeySequenceDataIndex
```

## Overview

Overview The Unicode keyboard-layout ( 'uchr') resource contains the data necessary to map virtual key codes to Unicode character codes for a given keyboard layout. The 'uchr' format consists of a header information section and five key mapping data sections. The UCKeySequenceDataIndex type is used in the fifth key mapping section of the 'uchr' resource. The UCKeySequenceDataIndex structure contains offsets to a list of character sequences for the 'uchr' resource. This permits a single keypress to generate a sequence of characters, or to generate a single character outside the range that can be represented directly by values of type  UCKeyOutput  or  UCKeyCharSeq.

## Topics

### Initializers

- [init()](coreservices/uckeysequencedataindex/1445802-init.md)
- [init(keySequenceDataIndexFormat:charSequenceCount:charSequenceOffsets:)](coreservices/uckeysequencedataindex/1442334-init.md)

### Instance Properties

- [charSequenceCount](coreservices/uckeysequencedataindex/1390623-charsequencecount.md)
- [charSequenceOffsets](coreservices/uckeysequencedataindex/1390466-charsequenceoffsets.md)
- [keySequenceDataIndexFormat](coreservices/uckeysequencedataindex/1390357-keysequencedataindexformat.md)