Printfn does not give expected results for international (non-Latin) characters

Question

I have the following program:

let txt = "إتصالات" printfn "Text is: %s" txt 0 // return an integer exit code 

The txt value is set to some Arabic characters. When I run the program, what is displayed on the console is a bunch of question marks, not characters. The Visual Studio 2012 debugger displays the correct characters for the txt variable.

What am I doing wrong and how to display international characters correctly?

Answer 1

According to How to write Unicode characters to the console? you need to set the OutputEncoding property on the console, for example:

 System.Console.OutputEncoding <- System.Text.Encoding.Unicode let txt = "إتصالات" printfn "Text is: %s" txt 0 // return an integer exit code 

The answer to this question is worth reading, because it also describes why you need to change your console font to really do the job, and also how to do it.

Here are some additional links with additional information:

• The necessary criteria for fonts to be available in the command window (this is for Windows 2000 and may not fully apply to Windows 8, but this should give you a good idea of ​​what to look for in the font).
• Windows consoles and TrueType fonts show how to add new fonts to the console.
• Anyone who says that the console cannot do Unicode is not as smart as they think they contain some background information about writing Unicode text to the console.

Update. Since the text in the Arabic text in the example just works fine on StackOverflow, I looked in CSS to see which fonts they use to render pre-formatted text. Using this list and the Windows Symbol Map tool (Start → All Programs → Accessories → System Tools → Symbol Map), I found that the Courier New font (which comes with Windows) supports Arabic characters. If you use the hacked registry in the link "Windows Console and TrueType Fonts" (see above), you can add Courier New as a font that you can use in the console.