Windows Unicode

As I understand it, Windows Unicode uses 2 bytes per character. In many cases, the upper byte is zero. This seems to be at least true for all characters up to lower case 'z' (0x7A). So the non-unicode string HELLO would be:-

Code:

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0x48 0x45 0x4C 0x4C 0x4F
  H    E    L    L    O

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whereas its unicode equivalent would be:-

Code:

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0x48 0x00 0x45 0x00 0x4C 0x00 0x4C 0x00 0x4F 0x00
  H        E        L        L        O

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At what point do we start getting a non-zero value in that upper byte? Is it after (say) character 0x7F? Or do all the first 256 characters give a zero value for the 2nd byte?

Basically, I'm trying to figure out if there's a way to convert (very simple) Windows unicode strings to single-byte strings on a non-Windows platform (i.e. where we don't have wcstombs() available). If I knew that each value was always going to be less than 256, could I do a cheap-and-dirty conversion by just taking every alternate byte?

Unicode
List of Unicode characters

Quote:

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Originally Posted by John E

Basically, I'm trying to figure out if there's a way to convert (very simple) Windows unicode strings to single-byte strings on a non-Windows platform (i.e. where we don't have wcstombs() available). If I knew that each value was always going to be less than 256, could I do a cheap-and-dirty conversion by just taking every alternate byte?

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Yes, if you can guarantee that the Unicode character set being used is Basic Latin and Latin Supplement, described here:

http://en.wikipedia.org/wiki/List_of_Unicode_characters

Otherwise, no.

Regards,

Paul McKenzie

Thanks guys. It's possible that I might not need it now but that's useful information to have.

Basically, my (cross-platform) app can launch a Windows child process. On Linux and OS-X this gets done via a utility called Wine. I might need to pass the child process a file path which will be in UTF-8 format in the main app. I wasn't sure whether Wine would convert the UTF-8 string to a format that Windows can understand - or whether I'd need to do that myself - but I've just been advised that Wine already takes care of this, so fingers crossed. ;)

If needed, you should be able to use <codecvt> ...

http://msdn.microsoft.com/en-us/libr...v=vs.100).aspx


Josuttis gives a few sample usages:

http://www.cppstdlib.com/

Click on "examples" , then "table of contents of all examples"[/url]

Scroll down to Section 16 ... Internationalization (last 5 examples in
the group).

Very useful links, Philip. Thanks!