The form 2#2ooo (where ooo is a 3 character octal value) can be used to index a known character code in a specific font encoding. For example the Adobe Symbol font uses a custom encoding in which octal 245 represents the infinity symbol. You could embed this in an enhanced text string by giving the font name and the character code "{/Symbol 2#2245}". This is mostly useful for the PostScript terminal, which cannot easily handle UTF-8 encoding.
You can specify a character by its Unicode code point as 2#2U+hhhh, where hhhh
is the 4 or 5 character hexadecimal code point. For example the code point for
the infinity symbol is 2#2U+221E. This will be converted to a UTF-8 byte
sequence on output if appropriate. In a UTF-8 environment this mechanism
is not needed for printable special characters since they are handled in a
text string like any other character. However it is useful for combining forms
or supplemental diacritical marks (e.g. an arrow over a letter to represent
a vector). See set encoding (p. ), utf8 (p.
), and the
http://www.gnuplot.info/demo_5.4/unicode.htmlonline unicode demo.