The Private Use Area consists of 6400 codepoints located from U+E000 to U+F8FF inclusive. Its formal title is the primary Private Use Area. It is often known simply as the Private Use Area (PUA).
The Unicode Standard presently also contains two other Private Use Areas. The other two Private Use Areas are located in planes fifteen and sixteen, where they each occupy all but two codepoints of a whole plane. They are known as Supplementary Private Use Area-A and Supplementary Private Use Area-B respectively.
Section 16.5 of the Unicode Standard has a section about the Private Use Area.
http://www.unicode.org/versions/Unicode5.0.0/ch16.pdf
Please note particularly the following sentence in that section.
quote
No assignment to a particular standard set of characters will ever be endorsed or documented by the Unicode Consortium for any of these code points.
end quote
Well, that seems to extend to not documenting that Microsoft, a major platform manufacturer, uses U+F020 to U+F0FF for symbol fonts. That non-documentation is fine as a legal principle, they treat a large corporation the same as an individual. However, for people trying to learn what is going on when using the Microsoft platform for fonts it is very difficult to find out the facts: I struggled with learning about this matter some years ago because I could not find the information!
That chapter and other chapters are available from the following web page.
http://www.unicode.org/versions/Unicode5.0.0/
As far as I can tell, and I may perhaps not be right in this, is that the symbol font structure is a way of having fonts with characters which respond to ordinary letters of the English alphabet and the other characters present on an American keyboard whilst internally having all of the glyphs mapped to the Unicode Private Use Area.
I do not encode fonts like that. If I want a shape to be displayed when a letter E key is pressed then I encode the font as an ordinary font and have the glyph for a letter E as the shape which I want. I have never had any problems with doing that and have not as yet found a situation where not using a symbol font as such has caused me any problems. However, I only have my own rather limited experiences and some other readers might be able to show some advantage to encoding a font as a symbol font.
The Private Use Area consists of 6400 codepoints located from U+E000 to U+F8FF inclusive.
Those numbers are expressed in hexadecimal notation.
If one expresses them in decimal notation one has the codepoint range of 57344 to 63743.
Some readers might like to know that Microsoft Calculator used in View Scientific mode is ideal for making such conversion from hexadecimal to decimal calculations and indeed for decimal to hexadecimal calculations as well.
U+F020 to U+F8FF which are hexadecimal converts into 61472 to 63743 decimal.
Please note that one can use the Private Use Area in an ordinary Unicode font, nothing to do with Microsoft symbol fonts. However, even though I know of no reason why I should, I do avoid using the range U+F000 to U+F0FF for my own code point allocations, just in case the Windows operating system is making any presumptions about for what those codepoints are being used.
As a side note, nothing to do with symbol fonts as far as I know, Microsoft used to use U+F001 and U+F002 for glyphs for the ligatures fi and fl in fonts. That started before U+FB01 and U+FB02 were assigned in regular Unicode. I read somewhere that Microsoft has formally stopped using those codepoints for those ligature glyphs. There are nonetheless a lot of fonts already in use where those codepoints are used for those ligature glyphs, sometimes the glyphs being mapped to both the Microsoft private codepoint allocations and the regular Unicode codepoint allocations in the same font.
William Overington
9 October 2007
