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  15 <b>wxWidgets 2 for Windows FAQ</b>
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  20
  21 <P>
  22
  23 See also <a href="faq.htm">top-level FAQ page</a>.
  24 <hr>
  25 <h3>List of questions in this category</h3>
  26 <ul>
  27 <li><a href="#platforms">Which Windows platforms are supported?</a></li>
  28 <li><a href="#wince">What about Windows CE?</a></li>
  29 <li><a href="#winxp">What do I need to do for Windows XP?</a></li>
  30 <li><a href="#compilers">What compilers are supported?</a></li>
  31 <li><a href="#bestcompiler">Which is the best compiler to use with wxWidgets 2?</a></li>
  32 <li><a href="#unicode">Is Unicode supported?</a></li>
  33 <li><a href="#doublebyte">Does wxWidgets support double byte fonts (Chinese/Japanese/Korean etc.)?</a></li>
  34 <li><a href="#dll">Can you compile wxWidgets 2 as a DLL?</a></li>
  35 <li><a href="#exesize">How can I reduce executable size?</a></li>
  36 <li><a href="#mfc">Is wxWidgets compatible with MFC?</a></li>
  37 <li><a href="#setuph">Why do I get errors about setup.h not being found?</a></li>
  38 <li><a href="#asuffix">Why do I get errors about FooBarA when I only use FooBar in my program?</a></li>
  39 <li><a href="#newerrors">Why my code fails to compile with strange errors about new operator?</a></li>
  40 <li><a href="#mfcport">How do I port MFC applications to wxWidgets?</a></li>
  41 <li><a href="#crash">Why do I sometimes get bizarre crash problems using VC++ 5/6?</a></li>
  42 <li><a href="#makefiles">How are the wxWidgets makefiles edited under Windows?</a></li>
  43 <li><a href="#vcdebug">How do you use VC++&#39;s memory leak checking instead of that in wxWidgets?</a></li>
  44 <li><a href="#shortcutproblem">Why are menu hotkeys or shortcuts not working in my application?</a></li>
  45 <li><a href="#regconfig">Why can I not write to the HKLM part of the registry with wxRegConfig?</a></li>
  46 <li><a href="#access">Is MS Active Accessibility supported?</a></li>
  47 <li><a href="#dspfmt">Why does Visual C++ complain about corrupted project files??</a></li>
  48 <li><a href="#crtmismatch">Visual C++ gives errors about multiply defined symbols, what can I do?</a></li>
  49 <li><a href="#directx">Why do I get compilation errors when using wxWidgets with DirectShow?</a></li>
  50 <li><a href="#handlewm">How do I handle Windows messages in my wxWidgets program?</a></li>
  51 </ul>
  52 <hr>
  53
  54 <h3><a name="platforms">Which Windows platforms are supported?</a></h3>
  55
  56 wxWidgets 2 can be used to develop and deliver applications on Windows 3.1, Win32s,
  57 Windows 95, Windows 98, Windows NT, Windows 2000, and Windows XP. A Windows CE
  58 version is being looked into (see below).<P>
  59
  60 wxWidgets 2 is designed to make use of WIN32 features and controls. However, unlike Microsoft,
  61 we have not forgotten users of 16-bit Windows. Most features
  62 work under Windows 3.1, including wxTreeCtrl and wxListCtrl using the generic implementation.
  63 However, don&#39;t expect very Windows-95-specific classes to work, such as wxTaskBarIcon. The wxRegConfig
  64 class doesn&#39;t work either because the Windows 3.1 registry is very simplistic. Check out the 16-bit
  65 makefiles to see what other files have been left out.
  66 <P>
  67 16-bit compilation is supported under Visual C++ 1.5, and Borland BC++ 4 to 5.
  68 <P>
  69
  70 wxWidgets 2 for Windows will also compile on Unix with gcc using Wine from <a href="http://www.winehq.org" target=_top>WineHQ</a>.
  71 The resulting executables are Unix binaries that work with the Wine Windows API emulator.<P>
  72
  73 You can also compile wxWidgets 2 for Windows on Unix with Cygwin or Mingw32, resulting
  74 in executables that will run on Windows. So in theory you could write your applications
  75 using wxGTK or wxMotif, then check/debug your wxWidgets for Windows
  76 programs with Wine, and finally produce an ix86 Windows executable using Cygwin/Mingw32,
  77 without ever needing a copy of Microsoft Windows. See the Technical Note on the Web site detailing cross-compilation.<P>
  78
  79 <h3><a name="wince">What about Windows CE?</a></h3>
  80
  81 This port is largely complete. For further information, see the <a href="http://www.wxwidgets.org/embedded.htm#wxwince">wxEmbedded</a> page.<P>
  82
  83 <h3><a name="winxp">What do I need to do for Windows XP?</a></h3>
  84
  85 In the same directory as you have your executable (e.g. foo.exe) you
  86 put a file called foo.exe.manifest in which you have something like
  87 the following:
  88
  89 <pre>
  90 &lt;?xml version="1.0" encoding="UTF-8" standalone="yes"?&gt;
  91 &lt;assembly
  92    xmlns="urn:schemas-microsoft-com:asm.v1"
  93    manifestVersion="1.0"&gt;
  94 &lt;assemblyIdentity
  95     processorArchitecture="x86"
  96     version="5.1.0.0"
  97     type="win32"
  98     name="foo.exe"/&gt;
  99     &lt;description&gt;Foo program&lt;/description&gt;
 100     &lt;dependency&gt;
 101     &lt;dependentAssembly&gt;
 102     &lt;assemblyIdentity
 103          type="win32"
 104          name="Microsoft.Windows.Common-Controls"
 105          version="6.0.0.0"
 106          publicKeyToken="6595b64144ccf1df"
 107          language="*"
 108          processorArchitecture="x86"/&gt;
 109     &lt;/dependentAssembly&gt;
 110     &lt;/dependency&gt;
 111 &lt;/assembly&gt;
 112 </pre>
 113
 114 If you want to add it to your application permanently,
 115 you can also include it in your .rc file using this
 116 line:<P>
 117
 118 <PRE>
 119   1 24 "winxp.manifest"
 120 </PRE>
 121
 122 In wxWidgets 2.5, this will be in the wx/msw/wx.rc and
 123 so will happen automatically so long as you include wx.rc
 124 in your own .rc file.<P>
 125
 126 For an explanation of this syntax, please see
 127 <a href="http://delphi.about.com/library/bluc/text/uc111601a.htm" target=_new>this
 128 article</a>.
 129 <P>
 130
 131 <h3><a name="compilers">What compilers are supported?</a></h3>
 132
 133 Please see the wxWidgets 2 for Windows install.txt file for up-to-date information, but
 134 currently the following are known to work:<P>
 135
 136 <ul>
 137 <li>Visual C++ 1.5, 4.0, 5.0, 6.0, 7.0, 7.1
 138 <li>Borland C++ 4.5, 5.0, 5.5
 139 <li>Borland C++Builder 1.0, 3.0, X
 140 <li>Watcom C++ 10.6 (Win32), OpenWatcom 1.0
 141 <li>Cygwin (using configure)
 142 <li>Mingw32
 143 <li>MetroWerks CodeWarrior (many versions)
 144 <li>Digital Mars 8.34+
 145 </ul>
 146 <P>
 147
 148
 149 <h3><a name="bestcompiler">Which is the best compiler to use with wxWidgets 2?</a></h3>
 150
 151 It&#39;s partly a matter of taste, but I (JACS) prefer Visual C++ since the debugger is very
 152 good, it&#39;s very stable, the documentation is extensive, and it generates small executables.
 153 Since project files are plain text, it&#39;s easy for me to generate appropriate project files
 154 for wxWidgets samples.<P>
 155
 156 Borland C++ is fine - and very fast - but it&#39;s hard (impossible?) to use the debugger without using project files, and
 157 the debugger is nowhere near up to VC++&#39;s quality. The IDE isn&#39;t great.<P>
 158
 159 C++Builder&#39;s power isn&#39;t really used with wxWidgets since it needs integration with its
 160 own class library (VCL). For wxWidgets, I&#39;ve only used it with makefiles, in which case
 161 it&#39;s almost identical to BC++ 5.0 (the same makefiles can be used).<P>
 162
 163 You can&#39;t beat Cygwin&#39;s price (free), and you can debug adequately using gdb. However, it&#39;s
 164 quite slow to compile since it does not use precompiled headers.<P>
 165
 166 CodeWarrior is cross-platform - you can debug and generate Windows executables from a Mac, but not
 167 the other way around I think - but the IDE is, to my mind, a bit primitive.<P>
 168
 169 Watcom C++ is a little slow and the debugger is not really up to today&#39;s standards.<P>
 170
 171 Among the free compilers the best choice seem to be Borland C++ command line
 172 tools and mingw32 (port of gcc to Win32). Both of them are supported by
 173 wxWidgets.
 174
 175 <h3><a name="unicode">Is Unicode supported?</a></h3>
 176
 177 Yes, Unicode is fully supported under Windows NT/2000 and there is limited
 178 support for it under Windows 9x using <a
 179 href="http://www.microsoft.com/globaldev/handson/dev/mslu_announce.mspx">MSLU</a>.
 180 <p>
 181
 182 <h3><a name="doublebyte">Does wxWidgets support double byte fonts (Chinese/Japanese/Korean etc.)?</a></h3>
 183
 184 For Japanese under Win2000, it seems that wxWidgets has no problems to work
 185 with double byte char sets (meaning DBCS, not Unicode). First you have to
 186 install Japanese support on your Win2K system and choose for ANSI translation
 187 <tt>HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\CodePage=932</tt>
 188 (default is 1252 for Western). Then you can see all the Japanese letters in
 189 wxWidgets applications.
 190 <p>
 191
 192 <h3><a name="dll">Can you compile wxWidgets 2 as a DLL?</a></h3>
 193
 194 Yes (using the Visual C++ or Borland C++ makefile), but be aware that distributing DLLs is a thorny issue
 195 and you may be better off compiling statically-linked applications, unless you&#39;re
 196 delivering a suite of separate programs, or you&#39;re compiling a lot of wxWidgets applications
 197 and have limited hard disk space.<P>
 198
 199 With a DLL approach, and with different versions and configurations of wxWidgets
 200 needing to be catered for, the end user may end up with a host of large DLLs in his or her Windows system directory,
 201 negating the point of using DLLs. Of course, this is not a problem just associated with
 202 wxWidgets!
 203 <P>
 204
 205 <h3><a name="exesize">How can I reduce executable size?</a></h3>
 206
 207 You can compile wxWidgets as a DLL (see above, VC++/BC++ only at present). You should also
 208 compile your programs for release using non-debugging and space-optimisation options, but
 209 take with VC++ 5/6 space optimisation: it can sometimes cause problems.<P>
 210
 211 If you want to distribute really small executables, you can
 212 use <a href="http://www.un4seen.com/petite/" target=_top>Petite</a>
 213 by Ian Luck. This nifty utility compresses Windows executables by around 50%, so your 500KB executable
 214 will shrink to a mere 250KB. With this sort of size, there is reduced incentive to
 215 use DLLs. Another good compression tool (probably better than Petite) is <a href="http://upx.sourceforge.net/" target=_top>UPX</a>.
 216 <P>
 217
 218 Please do not be surprised if MinGW produces a statically-linked minimal executable of 1 MB. Firstly, gcc
 219 produces larger executables than some compilers. Secondly, this figure will
 220 include most of the overhead of wxWidgets, so as your application becomes more
 221 complex, the overhead becomes proportionally less significant. And thirdly, trading executable compactness
 222 for the enormous increase in productivity you get with wxWidgets is almost always well worth it.<P>
 223
 224 If you have a really large executable compiled with MinGW (for example 20MB) then
 225 you need to configure wxWidgets to compile without debugging information: see
 226 docs/msw/install.txt for details. You may find that using configure instead
 227 of makefile.g95 is easier, particularly since you can maintain debug and
 228 release versions of the library simultaneously, in different directories.
 229 Also, run &#39;strip&#39; after linking to remove all traces of debug info.
 230 <P>
 231
 232 <H3><a name="mfc">Is wxWidgets compatible with MFC?</a></H3>
 233
 234 There is a sample which demonstrates MFC and wxWidgets code co-existing in the same
 235 application. However, don&#39;t expect to be able to enable wxWidgets windows with OLE-2
 236 functionality using MFC.<P>
 237
 238 <H3><a name="setuph">Why do I get errors about setup.h not being found?</a></H3>
 239
 240 When you build the wxWidgets library, setup.h is copied
 241 from include/wx/msw/setup.h to e.g. lib/mswd/wx/setup.h (the path
 242 depends on the configuration you&#39;re building). So you need to add
 243 this include path if building using the static Debug library:<P>
 244
 245 lib/mswd<P>
 246
 247 or if building the static Release library, lib/msw.<P>
 248
 249 See also the <a href="http://wiki.wxwidgets.org/wiki.pl?Table_Of_Contents">wxWiki Contents</a>
 250 for more information.<P>
 251
 252
 253 <H3><a name="asuffix">Why do I get errors about FooBarA when I only use FooBar in my program?</H3>
 254
 255 If you get errors like
 256 <p>
 257 <center>
 258 <tt>no matching function for call to &#39;wxDC::DrawTextA(const char[5], int,
 259 int)&#39;</tt>
 260 </center>
 261 <p>
 262 or similar ones for the other functions, i.e. the compiler error messages
 263 mention the function with the <tt>&#39;A&#39;</tt> suffix while you didn&#39;t
 264 use it in your code, the explanation is that you had included
 265 <tt>&#60;windows.h&#062;</tt> header which redefines many symbols to have such
 266 suffix (or <tt>&#39;W&#39;</tt> in the Unicode builds).
 267
 268 <p>
 269 The fix is to either not include <tt>&#60;windows.h&#62;</tt> at all or include
 270 <tt>"wx/msw/winundef.h"</tt> immediately after it.
 271
 272 <H3><a name="newerrors">Why my code fails to compile with strange errors about new operator?</a></H3>
 273
 274 The most common cause of this problem is the memory debugging settings in
 275 <tt>wx/msw/setup.h</tt>. You have several choices:
 276
 277 <ul>
 278     <li> Either disable overloading the global operator new completely by
 279          setting <tt>wxUSE_GLOBAL_MEMORY_OPERATORS</tt> and
 280          <tt>wxUSE_DEBUG_NEW_ALWAYS</tt> to 0 in this file
 281     <li> Or leave them on but do <tt>#undef new</tt> after including any
 282          wxWidgets headers, like this the memory debugging will be still on
 283          for wxWidgets sources but off for your own code
 284 </ul>
 285
 286 Notice that IMHO the first solution is preferable for VC++ users who can use
 287 the <a href="#vcdebug">VC++ CRT memory debugging features</a> instead.
 288
 289 <H3><a name="mfcport">How do I port MFC applications to wxWidgets?</a></H3>
 290
 291 Set up your interface from scratch using wxWidgets (especially <a href="http://www.robeling.de" target=_top>wxDesigner</a>
 292 or <a href="http://www.anthemion.co.uk/dialogblocks/" target=_new>DialogBlocks</a> --
 293 it&#39;ll save you a <i>lot</i> of time) and when you have a shell prepared, you can start
 294 &#39;pouring in&#39; code from the MFC app, with appropriate
 295 modifications. This is the approach I have used, and I found
 296 it very satisfactory. A two-step process then - reproduce the bare
 297 interface first, then wire it up afterwards. That way you deal
 298 with each area of complexity separately. Don&#39;t try to think MFC
 299 and wxWidgets simultaneously from the beginning - it is easier to
 300 reproduce the initial UI by looking at the behaviour of the MFC
 301 app, not its code.
 302
 303 <H3><a name="crash">Why do I sometimes get bizarre crash problems using VC++ 5/6?</a></H3>
 304
 305 Some crash problems can be due to inconsistent compiler
 306 options (and of course this isn&#39;t limited to wxWidgets).
 307 If strange/weird/impossible things start to happen please
 308 check (dumping IDE project file as makefile and doing text comparison
 309 if necessary) that the project settings, especially the list of defined
 310 symbols, struct packing, etc. are exactly the same for all items in
 311 the project. After this, delete everything (including PCH) and recompile.<P>
 312
 313 VC++ 5&#39;s optimization code seems to be broken and can
 314 cause problems: this can be seen when deleting an object Dialog
 315 Editor, in Release mode with optimizations on. If in doubt,
 316 switch off optimisations, although this will result in much
 317 larger executables. It seems possible that the library can be created with
 318 strong optimization, so long as the application is not strongly
 319 optimized. For example, in wxWidgets project, set to &#39;Minimum
 320 Size&#39;. In Dialog Editor project, set to &#39;Customize: Favor Small
 321 Code&#39; (and no others). This will then work.<P>
 322
 323 <H3><a name="makefiles">How are the wxWidgets makefiles edited under Windows?</a></H3>
 324
 325 As of wxWidgets 2.1, there is a new system written by Vadim Zeitlin, that
 326 generates the makefiles from templates using tmake.<P>
 327
 328 Here are Vadim&#39;s notes:<P>
 329
 330 <blockquote>
 331 To use these new makefiles, you don&#39;t need anything (but see below).
 332 However, you should NOT modify them because these files will be
 333 rewritten when I regenerate them using tmake the next time. So, if
 334 you find a problem with any of these makefiles (say, makefile.b32)
 335 you&#39;ll need to modify the corresponding template (b32.t in this
 336 example) and regenerate the makefile using tmake.<P>
 337
 338 tmake can be found at
 339 <a href="http://www.troll.no/freebies/tmake.html" target=_new>www.troll.no/freebies/tmake.html</a>.
 340 It&#39;s a Perl5 program and so it needs Perl (doh). There is a binary for
 341 Windows (available from the same page), but I haven&#39;t used it, so
 342 I don&#39;t know if it works as flawlessly as "perl tmake" does (note
 343 for people knowing Perl: don&#39;t try to run tmake with -w, it won&#39;t
 344 do you any good). Using it extremely simple: to regenerate makefile.b32
 345 just go to distrib/msw/tmake and type<P>
 346
 347 <pre>tmake -t b32 wxwin.pro -o ../../src/msw/makefile.b32</pre><P>
 348
 349 The makefiles are untested - I don&#39;t have any of Borland, Watcom  or
 350 Symantec and I don&#39;t have enough diskspace to recompile even with
 351 VC6 using makefiles. The new makefiles are as close as possible to the
 352 old ones, but not closer: in fact, there has been many strange things
 353 (should I say bugs?) in some of makefiles, some files were not compiled
 354 without any reason etc. Please test them and notify me about any problems.
 355 Better yet, modify the template files to generate the correct makefiles
 356 and check them in.<P>
 357
 358 The templates are described in tmake ref manual (1-2 pages of text)
 359 and are quite simple. They do contain some Perl code, but my Perl is
 360 primitive (very C like) so it should be possible for anybody to make
 361 trivial modifications to it (I hope that only trivial modifications
 362 will be needed). I&#39;ve tagged the old makefiles as MAKEFILES_WITHOUT_TMAKE
 363 in the cvs, so you can always retrieve them and compare the new ones,
 364 this will make it easier to solve the problems you might have.<P>
 365
 366 Another important file is filelist.txt: it contains the list of all
 367 files to be compiled. Some of them are only compiled in 16/32 bit mode.
 368 Some other are only compiled with some compilers (others can&#39;t compile
 369 them) - all this info is contained in this file.<P>
 370
 371 So now adding a new file to wxWidgets is as easy as modifying filelist.txt
 372 (and Makefile.ams for Unix ports) and regenerating the makefiles - no
 373 need to modify all files manually any more.<P>
 374
 375  Finally, there is also a file vc6.t which I use myself: this one
 376 generates a project file for VC++ 6.0 (I didn&#39;t create vc5.t because
 377 I don&#39;t need it and can&#39;t test it, but it should be trivial to create
 378 one from vc6.t - probably the only things to change would be the
 379 version number in the very beginning and the /Z option - VC5 doesn&#39;t
 380 support edit-and=continue). This is not an officially supported way
 381 of building wxWidgets (that is, nobody guarantees that it will work),
 382 but it has been very useful to me and I hope it will be also for
 383 others. To generate wxWidgets.dsp run<P>
 384
 385 <pre>tmake -t vc6 wxwin.pro -o ../../wxWidgets.dsp</pre><P>
 386
 387 Then just include this project in any workspace or open it from VC IDE
 388 and it will create a new workspace for you.<P>
 389
 390 If all goes well, I&#39;m planning to create a template file for Makefile.ams
 391 under src/gtk and src/motif and also replace all makefiles in the samples
 392 subdirectories with the project files from which all the others will be
 393 generated. At least it will divide the number of files in samples
 394 directory by 10 (and the number of files to be maintained too).
 395 </blockquote>
 396
 397 <P>
 398
 399 <H3><a name="vcdebug">How do you use VC++&#39;s memory leak checking instead of that in wxWidgets?</a></H3>
 400
 401 Vadim Zeitlin:
 402
 403 <pre>
 404 On the VC++ level, it&#39;s just the matter of calling _CrtSetDbgFlag() in the very
 405 beginning of the program. In wxWidgets, this is done automatically when
 406 compiling with VC++ in debug mode unless wxUSE_GLOBAL_MEMORY_OPERATORS or
 407 __NO_VC_CRTDBG__ are defined - this check is done in wx/msw/msvcrt.h which
 408 is included from app.cpp which then calls wxCrtSetDbgFlag() without any
 409 ifdefs.
 410
 411 This works quite well: at the end of the program, all leaked blocks with their
 412 malloc count are shown. This number (malloc count) can be used to determine
 413 where exactly the object was allocated: for this it&#39;s enough to set the variable
 414 _crtBreakAlloc (look in VC98\crt\srs\dbgheap.c line 326) to this number and
 415 a breakpoint will be triggered when the block with this number is allocated.
 416
 417 For simple situations it works like a charm. For something more complicated
 418 like reading uninitialized memory a specialized tool is probably better...
 419
 420 Regards,
 421 VZ
 422 </pre>
 423
 424 <P>
 425
 426 <H3><a name="shortcutproblem">Why are menu hotkeys or shortcuts not working in my application?</a></H3>
 427
 428 This can happen if you have a child window intercepting EVT_CHAR events and swallowing
 429 all keyboard input. You should ensure that event.Skip() is called for all input that
 430 isn&#39;used by the event handler.<P>
 431
 432 It can also happen if you append the submenu to the parent
 433 menu {\it before} you have added your menu items. Do the append {\it after} adding
 434 your items, or accelerators may not be registered properly.<P>
 435
 436 <H3><a name="#regconfig">Why can I not write to the HKLM part of the registry with wxRegConfig?</a></H3>
 437
 438 Currently this is not possible because the wxConfig family of classes is
 439 supposed to deal with per-user application configuration data, and HKLM is
 440 only supposed to be writable by a user with Administrator privileges. In theory,
 441 only installers should write to HKLM. This is still a point debated by the
 442 wxWidgets developers. There are at least two ways to work around it if you really
 443 need to write to HKLM.<P>
 444
 445 First, you can use wxRegKey directly, for example:
 446
 447 <pre>
 448     wxRegKey regKey;
 449
 450     wxString idName(wxT("HKEY_LOCAL_MACHINE\\SOFTWARE\\My Company\\My Product\\Stuff\\"));
 451     idName += packid;
 452
 453     regKey.SetName(idName);
 454
 455     {
 456         wxLogNull dummy;
 457         if (!regKey.Create())
 458         {
 459             idName = wxT("HKEY_CURRENT_USER\\SOFTWARE\\My Company\\My Product\\Stuff\\");
 460             idName += packid;
 461             regKey.SetName(idName);
 462             if (!regKey.Create())
 463                 return FALSE;
 464         }
 465     }
 466
 467     if (!regKey.SetValue(wxT("THING"), (long) thing)) err += 1;
 468
 469     regKey.Close();
 470
 471 </pre>
 472
 473 Or, you can employ this trick suggested by Istvan Kovacs:
 474
 475 <pre>
 476 class myGlobalConfig : public wxConfig
 477 {
 478     myGlobalConfig() :
 479         wxConfig ("myApp", "myCompany", "", "", wxCONFIG_USE_GLOBAL_FILE)
 480 {};
 481     bool Write(const wxString& key, const wxString& value);
 482 }
 483
 484 bool myGlobalConfig::Write (const wxString& key, const wxString& value)
 485 {
 486     wxString path = wxString ("SOFTWARE\\myCompany\\myApp\\") + wxPathOnly(key);
 487     wxString new_path = path.Replace ("/", "\\", true);
 488     wxString new_key = wxFileNameFromPath (key);
 489     LocalKey().SetName (wxRegKey::HKLM, path);
 490     return wxConfig::Write (new_key, value);
 491 }
 492 </pre>
 493
 494 <H3><a name="#access">Is MS Active Accessibility supported?</a></H3>
 495
 496 This is being worked on. Please see <a href="http://www.wxwidgets.org/access.htm">this page</a>
 497 for the current status.
 498
 499 <P>
 500
 501
 502 <h3><a name="#dspfmt">Why does Visual C++ complain about corrupted project files??</a></h3>
 503
 504 If you have downloaded the wxWidgets sources from the cvs using a Unix cvs
 505 client or downloaded a daily snapshot in <tt>.tar.gz</tt> format, it is likely
 506 that the project files have Unix line endings (LF) instead of the DOS ones (CR
 507 LF). However all versions of Visual C++ up to and including 7.1 can only open
 508 the files with the DOS line endings, so you must transform the files to this
 509 format using any of the thousands ways to do it.
 510 <p>
 511 Of course, another possibility is to always use only the Windows cvs client
 512 and to avoid this problem completely.
 513 <p>
 514
 515 <h3><a name="#crtmismatch">Visual C++ gives errors about multiply defined symbols, what can I do?</a></h3>
 516
 517 If you get errors like this
 518
 519 <pre>
 520 MSVCRTD.lib(MSVCRTD.dll) : error LNK2005: _xxxxxx already defined in LIBCD.lib(yyyyy.obj)
 521 </pre>
 522
 523 when linking your project, this means that you used different versions of CRT
 524 (C Run-Time) library for wxWindows (or possibly another library) and the main
 525 project. Visual C++ provides static or dynamic and multithread safe or not
 526 versions of CRT for each of debug and release builds, for a total of 8
 527 libraries. You can choose among them by going to the "Code generation"
 528 page/subitem of the "C++" tab/item in the project properties dialog in VC6/7.
 529 <p>
 530 To avoid problems, you <strong>must</strong> use the same one for all
 531 components of your project. wxWindows uses multithread safe DLL version of the
 532 CRT which is a good choice but may be problematic when distributing your
 533 applications if you don&#39;t include the CRT DLL in your installation -- in this
 534 case you may decide to switch to using a static CRT version. If you build with
 535 <tt>wxUSE_THREADS == 0</tt> you may also use the non MT-safe version as it is
 536 slightly smaller and faster.
 537 <p>
 538 But the most important thing is to use the <strong>same</strong> CRT setting for
 539 all components of your project.
 540
 541 <h3><a name="#directx">Why do I get compilation errors when using wxWidgets with DirectShow?</a></h3>
 542
 543 If you get errors when including Microsoft DirectShow or DirectDraw headers,
 544 the following message from Peter Whaite could help:
 545 <blockquote>
 546 &gt; This causes compilation errors within DirectShow:
 547 &gt;
 548 &gt; wxutil.h(125) : error C2065: &#39;EXECUTE_ASSERT&#39; : undeclared identifier
 549 &gt; amfilter.h(1099) : error C2065: &#39;ASSERT&#39; : undeclared identifier
 550
 551 The reason for this is that __WXDEBUG__ is also used by the DXSDK (9.0
 552 in my case) to &#39;#pragma once&#39; the contents of
 553 DXSDK/Samples/C++/DirectShow/BaseClasses/wxdebug.h.  So if __WXDEBUG__
 554 is defined, then wxdebug.h doesn&#39;t get included, and the assert macros
 555 don&#39;t get defined.  You have to #undef __WXDEBUG__ before including the
 556 directshow baseclass&#39;s &lt;streams.h&gt;.
 557 </blockquote>
 558
 559
 560 <h3><a name="#handlewm">How do I handle Windows messages in my wxWidgets program?</a></h3>
 561
 562 To handle a Windows message you need to override a virtual
 563 <tt>MSWWindowProc()</tt> method in a wxWindow-derived class. You should then
 564 test if <tt>nMsg</tt> parameter is the message you need to process and perform
 565 the necessary action if it is or call the base class method otherwise.
 566
 567
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