---
title: Key Format Codes
framework: coreservices
role: collectionGroup
path: coreservices/carbon_core/unicode_utilities/1390609-key_format_codes
---

# Key Format Codes

Indicate a structure format used in a 'uchr' resource.

## Overview

Overview These constants are those currently defined to be used within the various structures in a 'uchr' resource to indicate each structure’s format.

## Topics

### Constants

- [kUCKeyLayoutHeaderFormat](coreservices/kuckeylayoutheaderformat.md)
- [kUCKeyLayoutFeatureInfoFormat](coreservices/kuckeylayoutfeatureinfoformat.md)
- [kUCKeyModifiersToTableNumFormat](coreservices/kuckeymodifierstotablenumformat.md)
- [kUCKeyToCharTableIndexFormat](coreservices/kuckeytochartableindexformat.md)
- [kUCKeyStateRecordsIndexFormat](coreservices/kuckeystaterecordsindexformat.md)
- [kUCKeyStateTerminatorsFormat](coreservices/kuckeystateterminatorsformat.md)
- [kUCKeySequenceDataIndexFormat](coreservices/kuckeysequencedataindexformat.md)