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AIX Version 4 Keyboard Technical Reference

Understanding Nonspacing Characters

A nonspacing character sequence is a two-key sequence consisting of a diacritic mark followed by an alphabetic character.

Valid Sequences

Valid nonspacing character sequences are restricted to combinations of diacritical marks and alphabetic characters. Nonspacing character sequences are folded into a single character before passing the keyboard input to the application.

A special case exists when the nonspacing character sequence consists of a diacritic mark followed by a space. In this case, the diacritic mark is displayed and sent to the application.

A valid nonspacing character sequence causes a single accented character to be returned.

Examples of a valid nonspacing character are:

Valid Nonspacing Character Examples
1st Key Pressed 2nd Key Pressed Returned
Grave e e Grave - 1 character
Grave Space Grave accent - 1 character

Invalid Sequences

If the nonspacing character sequence is not valid, the LFT subsystem passes the nonspacing character to the application followed by the second character of the sequence. Nonspacing character sequences that are not valid include sequences that start with one of the following three parameters:

A nonspacing character sequence that is not valid returns the accent character, followed by the code for the key pressed after the nonspacing key.

Examples of an not valid nonspacing character are:

Not valid Nonspacing Character Examples
1st Key Pressed 2nd Key Pressed Returned
Grave z Grave accent - 2 z characters
Acute PF1 Acute accent (0xef) - 1 character PF1 (0x1b5b313731xx)

An not valid nonspacing character sequence (nonspacing character - nonspacing character) causes the first nonspacing character of the sequence to be passed to the application. The next nonspacing character starts a new nonspacing character sequence.


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