---
title: Special Handler Callback Constants
framework: coreservices
role: collectionGroup
path: coreservices/apple_events/1572726-special_handler_callback_constan
---

# Special Handler Callback Constants

Specify an object callback function to install, get, or remove from the special handler dispatch table.

## Overview

Overview You use these constants with the AEInstallSpecialHandler(_:_:_:), AEGetSpecialHandler(_:_:_:), or AERemoveSpecialHandler(_:_:_:) functions.

## Topics

### Constants

- [keyAERangeStart](coreservices/keyaerangestart.md)
- [keyAERangeStop](coreservices/keyaerangestop.md)
- [keyDisposeTokenProc](coreservices/keydisposetokenproc.md)
- [keyAECompareProc](coreservices/keyaecompareproc.md)
- [keyAECountProc](coreservices/keyaecountproc.md)
- [keyAEMarkTokenProc](coreservices/keyaemarktokenproc.md)
- [keyAEMarkProc](coreservices/keyaemarkproc.md)
- [keyAEAdjustMarksProc](coreservices/keyaeadjustmarksproc.md)
- [keyAEGetErrDescProc](coreservices/keyaegeterrdescproc.md)