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Unicode tip #9 - Console Output

Author: Bob Swart
Posted: 12/11/2008 12:29:22 PM (GMT+1)

First the bad news: console I/O does not support reading (UTF-16) Unicode strings, and writing only suports AnsiStrings. This means that as soon as you call write or writeln, the contents of a (unicode) string will be converted to AnsiString when needed, and written to the output.

This means that any Text file I/O needs to be rewritten using streams or other techniques. However, since a UTF8String is also an AnsiString (with the 65001 code page specified), there is a good workaround for writing to console output provided you set the console codepage to UTF-8 and use a font that can display the Unicode characters (that’s Lucida Console for example):

  program ConsoleUTF8;
Windows, SysUtils;

// Writeln(UTF8String('[???????????? ???????]')); // normal Unicode String, now "????"
Writeln(AnsiString('[наименование проекта]')); // UTF-8 cyrillic "hack"
This will produce cyrillic characters on the standard output, if you use Lucida Console as font (just try it - copy and paste into the Delphi 2009 IDE). Note that Lucida Console cannot display all Unicode characters – Chinese and the Clef are not shown, but at least cyrillic characters display without problems.

Note that I do not have to write the BOM to the output (you may want to in case you want to save the console output to a text file and read it afterwards. That way, you can set the font afterwards and also see the Chinese or Clef characters without problems. Provided they were written as UTF-8).

As long as we convert UTF-16 Unicode Strings to UTF-8 before writing to Text files, and don’t forget to use the UTF-8 BOM as prefix, this will work fine for writing files with Unicode UTF-8 output.

This tip is the 9th in a series of Unicode tips taken from my Delphi 2009 Development Essentials book published earlier this week on



fredG 08/12/11 13:42:44Are you saying that the programs writing unicode chars to the console do some kind of cheating? Or is this possible in C, but not in Delphi?
Bob Swart 08/12/11 14:02:14Delphi's console output is limited to AnsiStrings (and UTF8Strings are some kind of AnsiStrings as well). You cannot write UTF-16 Unicode Strings to the console output using Delphi without converting them to UTF-8 first. This may be possible in C, I don't know (don't care). Delphi needs UTF-8, and here I show how...
Marshall Fryman 08/12/11 19:31:58Using Vista, you can programmatically force the console font to be Lucinda using SetCurrentConsoleEx. Unfortunately, it's not possible with any older OS which limits its functionality. There's a good reference to older OS solutions here: If anyone is interested, you can't use WriteConsoleW and redirect to a text file (i.e., myprog > tst) because of how WriteConsoleW works. You have to detect the output mode as shown in this example : and use WriteConsoleW or WriteFile. You might also be interested to note that your solution works fine in Delphi 2007 also. m
Bob Swart 08/12/11 20:10:06Thanks for the feedback Marshall. is indeed an interesting link.

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