Guideline F: Coded character sets


F6: Respecting reserved code points



Respecting reserved code points

The allocation of code points is controlled by the guidelines of the encoding scheme. The scheme governs the code points that can be used for graphic characters, and which code points can be used for control characters.

Guideline F6


Do not use code points reserved by the encoding scheme for control characters as graphic characters; do not use code points reserved by the encoding scheme for graphic characters as control characters.

Example: A coded character set obeying the ISO/IEC 7-bit encoding scheme reserves 32 code points for control functions - X'00' to X'1F'. Your product requires 33 control codes, and uses the graphic code point X'20' for control as well. Unfortunately, you cannot allocate a control character in X'20' since this is specified by the encoding scheme to be the single-byte graphic character SPACE.