The Subversion API has a number of functions for converting from "natively-encoded" strings to strings that are encoded in UTF-8. My question is: what is this native encoding on Windows? Does it depend on locale?
"Natively encoded" strings are strings written in whatever code page the user is using. That is, they are numbers that are translated to the appropriate glyphs based on the correct code page. Assuming the file was saved that way and not as a UTF-8 file.
This is a candidate question for Joel's article on Unicode.
Specifically:
Eventually this OEM free-for-all got
codified in the ANSI standard. In the
ANSI standard, everybody agreed on
what to do below 128, which was pretty
much the same as ASCII, but there were
lots of different ways to handle the
characters from 128 and on up,
depending on where you lived. These
different systems were called code
pages. So for example in Israel DOS
used a code page called 862, while
Greek users used 737. They were the
same below 128 but different from 128
up, where all the funny letters
resided. The national versions of
MS-DOS had dozens of these code pages,
handling everything from English to
Icelandic and they even had a few
"multilingual" code pages that could
do Esperanto and Galician on the same
computer! Wow! But getting, say,
Hebrew and Greek on the same computer
was a complete impossibility unless
you wrote your own custom program that
displayed everything using bitmapped
graphics, because Hebrew and Greek
required different code pages with
different interpretations of the high
numbers.
Windows 1252. Jukka Korpela has an excellent page on character encodings, with an extensive discussion of the Windows character set.
From the header svn_string.h you can see that the relevant svn_strings are just plain old const char* + a length element.
I would guess that the "natively encoded" svn strings are interpreted according to your system locale (I do not know this for sure, but this is the convention). On Windows 7 you can check your locale by selecting "Start-->Control Panel-->Region and Language-->Administrative-->Change system locale" where any value of English would probably entail the character encoding Windows 1252. However, a different system locale, for example Hebrew (Israel), would entail a different character encoding (Windows 1255 for the case of Hebrew).
Sadly the MSVC version of the C library does not support UTF-8 and uses legacy codepages only, but cygwin provides a UTF-8 locale as part of its emulation layer. If your svn is built on cygwin, you should be able to use UTF-8 just fine.
Related
We have an MFC Windows Application, written originally in VC++ 6 and over the years updated for newer IDE, currently developed in VS2017.
The application is built with MBCS (not unicode). Trying to switch to Unicode causes 3806 compile errors, and that is probably just a tip of an iceberg.
However we want to be able to run the application with different code page, ie. 1250 (Central European).
I tried to build a small test application, and managed to get it to work with special characters (čćšđž). I did this by setting dialog font to Microsoft Sans Serif with code page 1250.
The same approach in our application does not work. Note: dialogs in our application are created dynamically, and font is set using SetFont.
There is a difference how the special characters are treated in these two applications.
In test application, the special characters are displayed in the edit control, and GetWindowsText retrieves the right bytes. However, trying to write some characters from other languages, renders them as "????".
In our application, all special characters are rendered properly, but GetWindowText (or WM_GETTEXT) convert the special characters to the similar ascii counterpart (čćđ -> ccd).
I believe that Edit control in our application displays Unicode text, but GetWindowText converts it to ascii.
Does anyone have any idea what is happening here, and how I might solve it?
Note: I know how to convert project to Unicode. We are choosing not to commit resources to it at the moment, as it would probably take weeks or months to implement. The question is how I might get it to work with MBSC and why is edit control converting Č to C.
I believe it is absolutely possible to port the application to other languages/codepages, you only need to modify the .rc (resource) files, basically having one resource file for each language, which you may rather want to do anyway, as strings in menus and/or string-tables would be in a different language. And this is actually the only change needed, as far as the application part is concerned.
The other part is the system you are running it on. A window can be unicode or non-unicode. You can see this with the Spyxx utility, it tells you whether a window (procedure) is unicode or not (Window properties, General tab). And while unicode windows do work properly, non-unicode ones have to change encoding from/to unicode and mbcs when getting or setting the text. The conversion is based on the system (default) code-page. This can only be set globally (for the whole machine), and not per application or window. And of course, setting the font's codepage is not enough (and imo it's not needed at all, if you are runnign the application on a machine with the "correct" codepage). That is, for non-unicode applications, only one codepage will be working properly, the others won't.
I can see two options:
If you only need to update a small number of controls, it may be possible to change only these controls to unicode, and use the "wide" versions of the get/set window-test functions or messages - you will have to convert the text between unicode and your desired codepage. It requires writing some code, but has the advantage of the conversion being independent from the system default codepage, eg you can have the codepage in some configuration file, in the registry, or as a command-line option (in the application's shortcut). Some control types can be changed to unicode, some others not, so pls check the documentation. Used this technique successfully for a mbcs application displaying/editing translated strings in many different languages, but I only had one control, a List-View, which btw offers the LVM_SETUNICODEFORMAT message, thus allowing for unicode texts, even in a mbcs application.
The easiest method is simply run the application as is, but it will only be working on machines with the proper default codepage, as most non-unicode applications do.
The system default codepage can be changed by setting the "Language for non-Unicode programs" option, available in the regional settings, Administrative tab, and requires a reboot. Changing the Windows UI language will change this option as well, but by setting this option you don't need to change the UI language, eg you can have English UI and East-European codepage.
See a very similar post here.
Late to the party:
In our application, all special characters are rendered properly, but GetWindowText (or WM_GETTEXT) convert the special characters to the similar ascii counterpart (čćđ -> ccd).
That sounds like the ES_OEMCONVERT flag has been set for the control:
Converts text entered in the edit control. The text is converted from the Windows character set to the OEM character set and then back to the Windows character set. This ensures proper character conversion when the application calls the CharToOem function to convert a Windows string in the edit control to OEM characters. This style is most useful for edit controls that contain file names that will be used on file systems that do not support Unicode.
To change this style after the control has been created, use SetWindowLong.
My requirement is to display string of any language on the screen.
Currently we are using opengl to display English characters.
Same APIs are not working for other languages. Instead of characters, boxes are displayed on screen.
Can someone help in understanding opengl and find appropriate APIs to display charterers of any language?
Currently we are using opengl to display English characters.
No, you're not using OpenGL. How do I know this? Because OpenGL does not do text rendering. All it does it points, lines and triangles.
What you're using is some library that knows how to draw characters with points, lines and triangles and then uses OpenGL to get that job done. And the particular library you're using apparently doesn't know, how to deal with characters outside of the ASCII character set.
Of course it's not just that what matters. Encoding matters as well. The most recent versions of C++ support Unicode in program sources (so that you can write unicode in string literals), but that does not automatically give you unicode support in your program – it's just the compiler who knows how to deal with it, but that knowledge does not automatically transpire into the compiled program.
So far there is only one operating system in which Unicode support is so deeply ingrained that no extra work is required; in fact a particular way of encoding Unicode was invented for it, but unfortunately this is one of the most niche OS projects there is around: Plan9
Apart from Unicode, there are also many other character encoding schemes, all incompatible with each other, each for a particular kind of writing. Which means, that it's also impossible to mix characters from different writing systems in texts encoding with such localized characters sets. Hence a universal encoding scheme was invented.
You're most likely on Windows, Linux, BSD, Solaris or MacOS X. And in all of them making non-ASCII-characters work means extra work for you, the programmer. MacOS X is probably the one OS with the least barrier of entry.
So here are the questions you have to answer for yourself:
what character encoding used (hopefully Unicode)?
does the text renderer library used support code points in that encoding?
does the text renderer library come with a layout engine (the thing that positions characters) or does this have to be supplied extra?
Among the existing text renderers that can draw to OpenGL, currently Freetype-GL is the most capable; it has support for Unicode
https://github.com/rougier/freetype-gl
I have to maintain a small C++ / VS2015 project in my department which only checks the installed .NET Framework of a machine and prompts the user if the current version is not installed. This small application is localized by a file called Language.rc which contains some STRINGTABLES with the corresponding texts.
All this works fine if the program is compiled on my machine, but if the same code is compiled on our build machines then the special characters like for example the German ÄÖÜ are missing.
Unfortunately I'm not a c++ person and I have no clue what is wrong. I already searched the web but cannot find a hint on what might be the problem.
Does anybody have an idea what could be different on the build machines compared to my machine that causes the different characters?
UPDATE:
So after my TFS expert has analysed the problem on the build machines we were able to identify the culprit:
As I said before the application that was causing the problem is only a small tool. Our automatic build contains a lot more solutions and projects. One part of the automatic build is a script that sets the version numbers of all kinds of files to the same value. This is apparently also done for so called RC files. As far as I understand there are different kinds of RC files in C++ (and also in Delpi) which actually hold version numbers. The RC file in my case only has texts and translations but is opened and also saved even though it does not have a version number.
Unfortunately this operation also explicitly sets the encoding of the file to some old IBMxyz encoding (maybe for the Delphi RC files?). This is the actual operations where the special characters get lost... So the solution to my problem is not within the original encoding of the file but somewhere in the build process.
As a temporary fix we changed the .rc file to an .rc2 file - this way the project still compiles but the build does no longer modify it.
I've had enough fun for today...
Windows has two ways of handling text. These are known as "Unicode" (really UTF-16) and "ANSI" (which isn't related to the ANSI standards organization, and describes any 8 bit superset of ASCII).
Your problem is clearly a case of "ANSI" disease. ASCII does not contain "Ä", some supersets of ASCII do, but not all supersets do. Different machines using different supersets will cause different results.
The "simple" fix is to prefix an L to the string in the .rc file: L"zum Beispiel", and then save this .rc file as Unicode (UTF-16). While newer versions of Windows contain more UTF-16 characters, this never affects existing characters, and Ä has been part of every Unicode version. (Even € works everywhere - I think that was added in Windows 2000)
I have software originally developed 20 years ago in Visual C++ using MFC without UNICODE. Currently strings are held either in char[] or CString, and it works on English and Japanese Windows PCs until Japanese characters are used, as these tend to get converted to strange characters or empty boxes.
Setting UNICODE is presumably the way forward but will require a massive code change, whereas quite a lot seems to work simply by setting System Locale to Japan (in “Window’s Language for non-Unicode programs” setting). I have no idea how Windows does this, but some Japanese character things now work on my English Windows PC, e.g. I can open and save Japanese filenames with no code changes. And in Japan they set System Locale to English and again much works, but not everything.
I get the impression the problems are due to using a font that doesn’t include Japanese characters. Currently I am using Arial / MS Sans Serif and charset set to ANSI_CHARSET or DEFAULT_CHARSET. Is there a different font I should be using, or can I extend these fonts to include Japanese characters? Or am I barking up the wrong tree in which case what do I do next? Am very new to all this unfortunately …
That's a common question (OK I guess not so common any more in 2015, as MBCS programs luckily are a dying breed - I still maintain several though...)
Either way, I'm afraid that, depending on your definition of 'working', to get this working you'll have to bite the bullet and convert to a Unicode build. If you can't make a business case for that, then you'll have to set the right locale (well, worse, have the user set the 'right' one) and test what works and what doesn't, and ask more specific questions on what doesn't.
If your goal is to make one application that correctly displays strings in various encodings in the 'right' way regardless of the locale settings on the computer, and compatible with every input data set / database content without the user having to be aware of encoding issues, then you're out of luck with an MBCS build.
The font missing characters is most likely not the problem. Before you go any further and/or ask further questions, you should read http://www.joelonsoftware.com/articles/Unicode.html, read it again, sleep on it, read it again, explain to somebody else what the relationship is between 'encoding', 'locale', 'character set', 'font' and 'Unicode code point', because only after you can do that, you can decide on how to progress with your application. Sorry, it's not what you want to hear, but it's the reality if you've been tasked with handling internationalization.
I am finishing application in Visual C++/Windows API and I am using MySql C Connector.
Whole application code uses ANSI, MySql C Connector is in ANSI too.
This program will be used on Polish and German computers with Windows XP/Vista/7 or 8.
I want to correcly display german umlauts and polish accent characters on:
DialogBox controls (strings are loaded from language files)
Generated XHTML documents
Strings retrieved from MySql database displayed on controls and in XHTML documents
I have heard about MultiByteToWideChar and Unicode functions (MessageBoxW etc.), but application code is nearly finished, converting is a lot of work...
How to make character encoding correctly with the least work and time?
Maybe changing system code page for non-Unicode program?
First, of course: what code set is MySQL returning? Or perhaps:
what code set was used when writing the data into the data base?
Other than that, I don't think you'll be able to avoid using
either wide characters or multibyte characters: for single byte
characters, German would use ISO 8859-1 (code page 1252) or
ISO 8859-15, Polish ISO 8859-2 (code page 1250). But what are
you doing with the characters in your own code? You may be able
to get away with UTF-8 (code page 65001), without many changes.
The real question is where the characters originally come from
(although it might not be too difficult to translate them into
UTF-8 immediately at the source); I don't think that Windows
respects the code page for input.
Although it doesn't help you much to know it, you're dealing
with an almost impossible problem, since so much depends on
things outside your program: things like the encoding of the
display font, or the keyboard driver, for example. In fact,
it's not rare for programs to display one thing on the screen,
and something different when outputting to the printer, or to
display one thing on the screen, but something different if the
data is written to a file, and read with another program. The
situation is improving—modern Unix and the Internet are
gradually (very gradually) standardizing on UTF-8, everywhere
and for everything, and Windows normally uses UTF-16 for
everything that is pure Windows (but needs to support UTF-8 for
the Internet). But even using the platform standard won't help
if the human client has installed (and is using) fonts which
don't have the characters you need.