# Metadata
Platforms: desktop, server OS: linux Introduced: 1.0 Security:
# Syntax
set the extendKey to keyNumber
# Examples
set the extendKey to 6 -- disables entry of high-bit chars
# Description
Use the extendKey property to specify how to create special characters, or to prevent users from typing special characters.
The extendKey specifies the modifier key used to toggle the high bit of characters on and off. Use the "xmodmap" program to find out which key is used for mod5 (or the modifier key specified for the extendKey).
To enter a high-bit character, press the modifier key, then type the key that corresponds to that character, then press the modifier key again to return to entering regular ASCII characters.
If the extendKey is greater than 5, entry of high-bit characters is disabled.
The setting of this property has no effect on Mac OS and Windows systems.
# Tags
ui,
# See
- **keyword:** characters, integer - **message:** keyDown - **function:** numToChar, charToNum - **glossary:** property, Unix, bit, ASCII, modifier key