wxWindows 2 for Windows FAQ

See also top-level FAQ page.

List of questions in this category

Which Windows platforms are supported?

wxWindows 2 can be used to develop and deliver applications on Windows 3.1, Win32s, Windows 95, Windows 98, Windows NT, Windows 2000, and Windows XP. A Windows CE version is being looked into (see below).

wxWindows 2 is designed to make use of WIN32 features and controls. However, unlike Microsoft, we have not forgotten users of 16-bit Windows. Most features work under Windows 3.1, including wxTreeCtrl and wxListCtrl using the generic implementation. However, don't expect very Windows-95-specific classes to work, such as wxTaskBarIcon. The wxRegConfig class doesn't work either because the Windows 3.1 registry is very simplistic. Check out the 16-bit makefiles to see what other files have been left out.

16-bit compilation is supported under Visual C++ 1.5, and Borland BC++ 4 to 5.

wxWindows 2 for Windows will also compile on Unix with gcc using TWIN32 from Willows, although TWIN32 is still in a preliminary state. The resulting executables are Unix binaries that work with the TWIN32 Windows API emulator.

You can also compile wxWindows 2 for Windows on Unix with Cygwin or Mingw32, resulting in executables that will run on Windows. So in theory you could write your applications using wxGTK or wxMotif, then check/debug your wxWindows for Windows programs with TWIN32, and finally produce an ix86 Windows executable using Cygwin/Mingw32, without ever needing a copy of Microsoft Windows. See the Technical Note on the Web site detailing cross-compilation.

What about Windows CE?

This is under consideration, though we need to get wxWindows Unicode-aware first. There are other interesting issues, such as how to combine the menubar and toolbar APIs as Windows CE requires. But there's no doubt that it will be possible, albeit by mostly cutting down wxWindows 2 API functionality, and adding a few classes here and there. Since wxWindows for 2 produces small binaries (less than 300K for the statically-linked 'minimal' sample), shoehorning wxWindows 2 into a Windows CE device's limited storage should not be a problem.

What do I need to do for Windows XP?

In the same directory as you have your executable (e.g. foo.exe) you put a file called foo.exe.manifest in which you have something like the following: 
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly
   xmlns="urn:schemas-microsoft-com:asm.v1"
   manifestVersion="1.0">
<assemblyIdentity
    processorArchitecture="x86"
    version="5.1.0.0"
    type="win32"
    name="foo.exe"/>
    <description>Foo program</description>
    <dependency>
    <dependentAssembly>
    <assemblyIdentity
         type="win32"
         name="Microsoft.Windows.Common-Controls"
         version="6.0.0.0"
         publicKeyToken="6595b64144ccf1df"
         language="*"
         processorArchitecture="x86"/>
    </dependentAssembly>
    </dependency>
</assembly>

What compilers are supported?

Please see the wxWindows 2 for Windows install.txt file for up-to-date information, but currently the following are known to work:

There is a linking problem with Symantec C++ which I hope someone can help solve.

Which is the best compiler to use with wxWindows 2?

It's partly a matter of taste, but I (JACS) prefer Visual C++ since the debugger is very good, it's very stable, the documentation is extensive, and it generates small executables. Since project files are plain text, it's easy for me to generate appropriate project files for wxWindows samples.

Borland C++ is fine - and very fast - but it's hard (impossible?) to use the debugger without using project files, and the debugger is nowhere near up to VC++'s quality. The IDE isn't great.

C++Builder's power isn't really used with wxWindows since it needs integration with its own class library (VCL). For wxWindows, I've only used it with makefiles, in which case it's almost identical to BC++ 5.0 (the same makefiles can be used).

You can't beat Cygwin's price (free), and you can debug adequately using gdb. However, it's quite slow to compile since it does not use precompiled headers.

CodeWarrior is cross-platform - you can debug and generate Windows executables from a Mac, but not the other way around I think - but the IDE is, to my mind, a bit primitive.

Watcom C++ is a little slow and the debugger is not really up to today's standards.

Among the free compilers the best choice seem to be Borland C++ command line tools and mingw32 (port of gcc to Win32). Both of them are supported by wxWindows.

Is Unicode supported?

Yes, Unicode is fully supported under Windows NT/2000 (Windows 9x don't have Unicode support anyhow).

Does wxWindows support double byte fonts (Chinese/Japanese/Korean etc.)?

An answer from Klaus Goedde:

"For Japanese under Win2000, it seems that wxWindows has no problems to work with double byte char sets (I mean DBCS, that's not Unicode). First you have to install Japanese support on your Win2K system and choose for ANSI translation HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\CodePage=932 (default is 1252 for Western). Then you can see all the funny Japanese letters under wxWindows too.

In a wxTextCtrl control you have to set the window style "wxTE_RICH", otherwise this control shows the wrong letters. I don't now whether it works on non W2K systems, because I'm just starting using wxWindows."

Can you compile wxWindows 2 as a DLL?

Yes (using the Visual C++ or Borland C++ makefile), but be aware that distributing DLLs is a thorny issue and you may be better off compiling statically-linked applications, unless you're delivering a suite of separate programs, or you're compiling a lot of wxWindows applications and have limited hard disk space.

With a DLL approach, and with different versions and configurations of wxWindows needing to be catered for, the end user may end up with a host of large DLLs in his or her Windows system directory, negating the point of using DLLs. Of course, this is not a problem just associated with wxWindows!

How can I reduce executable size?

You can compile wxWindows as a DLL (see above, VC++/BC++ only at present). You should also compile your programs for release using non-debugging and space-optimisation options, but take with VC++ 5/6 space optimisation: it can sometimes cause problems.

Statically-linked wxWindows 2 programs are smaller than wxWindows 1.xx programs, because of the way wxWindows 2 has been designed to reduce dependencies between classes, and other techniques. The linker will not include code from the library that is not (directly or indirectly) referenced by your application. So for example, the 'minimal' sample is less than 300KB using VC++ 6.

If you want to distribute really small executables, you can use Petite by Ian Luck. This nifty utility compresses Windows executables by around 50%, so your 500KB executable will shrink to a mere 250KB. With this sort of size, there is reduced incentive to use DLLs. Another good compression tool is UPX.

Is wxWindows compatible with MFC?

There is a sample which demonstrates MFC and wxWindows code co-existing in the same application. However, don't expect to be able to enable wxWindows windows with OLE-2 functionality using MFC.

Why do I get errors about FooBarA when I only use FooBar in my program?

If you get errors like

no matching function for call to 'wxDC::DrawTextA(const char[5], int, int)'

or similar ones for the other functions, i.e. the compiler error messages mention the function with the 'A' suffix while you didn't use it in your code, the explanation is that you had included <windows.h> header which redefines many symbols to have such suffix (or 'W' in the Unicode builds).

The fix is to either not include <windows.h> at all or include "wx/msw/winundef.h" immediately after it.

Why my code fails to compile with strange errors about new operator?

The most common cause of this problem is the memory debugging settings in wx/msw/setup.h. You have several choices: Notice that IMHO the first solution is preferable for VC++ users who can use the VC++ CRT memory debugging features instead.

How do I port MFC applications to wxWindows?

Set up your interface from scratch using wxWindows (especially wxDesigner -- it'll save you a lot of time) and when you have a shell prepared, you can start 'pouring in' code from the MFC app, with appropriate modifications. This is the approach I have used, and I found it very satisfactory. A two-step process then - reproduce the bare interface first, then wire it up afterwards. That way you deal with each area of complexity separately. Don't try to think MFC and wxWindows simultaneously from the beginning - it is easier to reproduce the initial UI by looking at the behaviour of the MFC app, not its code.

Why do I sometimes get bizarre crash problems using VC++ 5/6?

Some crash problems can be due to inconsistent compiler options (and of course this isn't limited to wxWindows). If strange/weird/impossible things start to happen please check (dumping IDE project file as makefile and doing text comparison if necessary) that the project settings, especially the list of defined symbols, struct packing, etc. are exactly the same for all items in the project. After this, delete everything (including PCH) and recompile.

VC++ 5's optimization code seems to be broken and can cause problems: this can be seen when deleting an object Dialog Editor, in Release mode with optimizations on. If in doubt, switch off optimisations, although this will result in much larger executables. It seems possible that the library can be created with strong optimization, so long as the application is not strongly optimized. For example, in wxWindows project, set to 'Minimum Size'. In Dialog Editor project, set to 'Customize: Favor Small Code' (and no others). This will then work.

How are the wxWindows makefiles edited under Windows?

As of wxWindows 2.1, there is a new system written by Vadim Zeitlin, that generates the makefiles from templates using tmake.

Here are Vadim's notes:

To use these new makefiles, you don't need anything (but see below). However, you should NOT modify them because these files will be rewritten when I regenerate them using tmake the next time. So, if you find a problem with any of these makefiles (say, makefile.b32) you'll need to modify the corresponding template (b32.t in this example) and regenerate the makefile using tmake.

tmake can be found at www.troll.no/freebies/tmake.html. It's a Perl5 program and so it needs Perl (doh). There is a binary for Windows (available from the same page), but I haven't used it, so I don't know if it works as flawlessly as "perl tmake" does (note for people knowing Perl: don't try to run tmake with -w, it won't do you any good). Using it extremely simple: to regenerate makefile.b32 just go to distrib/msw/tmake and type

tmake -t b32 wxwin.pro -o ../../src/msw/makefile.b32

The makefiles are untested - I don't have any of Borland, Watcom or Symantec and I don't have enough diskspace to recompile even with VC6 using makefiles. The new makefiles are as close as possible to the old ones, but not closer: in fact, there has been many strange things (should I say bugs?) in some of makefiles, some files were not compiled without any reason etc. Please test them and notify me about any problems. Better yet, modify the template files to generate the correct makefiles and check them in.

The templates are described in tmake ref manual (1-2 pages of text) and are quite simple. They do contain some Perl code, but my Perl is primitive (very C like) so it should be possible for anybody to make trivial modifications to it (I hope that only trivial modifications will be needed). I've tagged the ol makefiles as MAKEFILES_WITHOUT_TMAKE in the cvs, so you can always retrieve them and compare the new ones, this will make it easier to solve the problems you might have.

Another important file is filelist.txt: it contains the list of all files to be compiled. Some of them are only compiled in 16/32 bit mode. Some other are only compiled with some compilers (others can't compile them) - all this info is contained in this file.

So now adding a new file to wxWindows is as easy as modifying filelist.txt (and Makefile.ams for Unix ports) and regenerating the makefiles - no need to modify all files manually any more.

Finally, there is also a file vc6.t which I use myself: this one generates a project file for VC++ 6.0 (I didn't create vc5.t because I don't need it and can't test it, but it should be trivial to create one from vc6.t - probably the only things to change would be the version number in the very beginning and the /Z option - VC5 doesn't support edit-and=continue). This is not an officially supported way of building wxWindows (that is, nobody guarantees that it will work), but it has been very useful to me and I hope it will be also for others. To generate wxWindows.dsp run

tmake -t vc6 wxwin.pro -o ../../wxWindows.dsp

Then just include this project in any workspace or open it from VC IDE and it will create a new workspace for you.

If all goes well, I'm planning to create a template file for Makefile.ams under src/gtk and src/motif and also replace all makefiles in the samples subdirectories with the project files from which all the others will be generated. At least it will divide the number of files in samples directory by 10 (and the number of files to be maintained too).

How do you use VC++'s memory leak checking instead of that in wxWindows?

Vadim Zeitlin: 
On the VC++ level, it's just the matter of calling _CrtSetDbgFlag() in the very
beginning of the program. In wxWindows, this is done automatically when
compiling with VC++ in debug mode unless wxUSE_GLOBAL_MEMORY_OPERATORS or
__NO_VC_CRTDBG__ are defined - this check is done in wx/msw/msvcrt.h which
is included from app.cpp which then calls wxCrtSetDbgFlag() without any
ifdefs.

This works quite well: at the end of the program, all leaked blocks with their
malloc count are shown. This number (malloc count) can be used to determine
where exactly the object was allocated: for this it's enough to set the variable
_crtBreakAlloc (look in VC98\crt\srs\dbgheap.c line 326) to this number and
a breakpoint will be triggered when the block with this number is allocated.

For simple situations it works like a charm. For something more complicated
like reading uninitialized memory a specialized tool is probably better...

Regards,
VZ

Why are menu hotkeys or shortcuts not working in my application?

This can happen if you have a child window intercepting EVT_CHAR events and swallowing all keyboard input. You should ensure that event.Skip() is called for all input that isn'used by the event handler.

Why can I not write to the HKLM part of the registry with wxRegConfig?

Currently this is not possible because the wxConfig family of classes is supposed to deal with per-user application configuration data, and HKLM is only supposed to be writeable by a user with Administrator privileges. In theory, only installers should write to HKLM. This is still a point debated by the wxWindows developers. There are at least two ways to work around it if you really need to write to HKLM.

First, you can use wxRegKey directly, for example: 

    wxRegKey regKey;

    wxString idName(wxT("HKEY_LOCAL_MACHINE\\SOFTWARE\\My Company\\My Product\\Stuff\\"));
    idName += packid;

    regKey.SetName(idName);

    {
        wxLogNull dummy;  
        if (!regKey.Create())
        {
            idName = wxT("HKEY_CURRENT_USER\\SOFTWARE\\My Company\\My Product\\Stuff\\");
            idName += packid;
            regKey.SetName(idName);
            if (!regKey.Create())
                return FALSE;
        }
    }

    if (!regKey.SetValue(wxT("THING"), (long) thing)) err += 1;

    regKey.Close();
Or, you can employ this trick suggested by Istvan Kovacs: 
class myGlobalConfig : public wxConfig
{
    myGlobalConfig() :
        wxConfig ("myApp", "myCompany", "", "", wxCONFIG_USE_GLOBAL_FILE)
{};
    bool Write(const wxString& key, const wxString& value);
}

bool myGlobalConfig::Write (const wxString& key, const wxString& value)
{
    wxString path = wxString ("SOFTWARE\\myCompany\\myApp\\") + wxPathOnly(key);
    wxString new_path = path.Replace ("/", "\\", true);
    wxString new_key = wxFileNameFromPath (key);
    LocalKey().SetName (wxRegKey::HKLM, path);
    return wxConfig::Write (new_key, value);
}