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	5	<TITLE>wxWidgets for Windows FAQ</TITLE>
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	8	<BODY BGCOLOR=#FFFFFF TEXT=#000000 VLINK="#00376A" LINK="#00529C" ALINK="#313063">
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	10	<font face="Arial, Lucida Sans, Helvetica">
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	12	<table width=100% border=0 cellpadding=3 cellspacing=0>
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	15	<font size=+1 face="Arial, Lucida Sans, Helvetica" color="#FFFFFF">
	16	<b>wxWidgets for Windows FAQ</b>
	17	</font>
	18	</td>
	19	</tr>
	20	</table>
	21
	22	<P>
	23
	24	See also <a href="faq.htm">top-level FAQ page</a>.
	25	<hr>
	26	<h3>List of questions in this category</h3>
	27	<ul>
	28	<li><a href="#platforms">Which Windows platforms are supported?</a></li>
	29	<li><a href="#wince">What about Windows CE?</a></li>
	30	<li><a href="#winxp">What do I need to do for Windows XP?</a></li>
	31	<li><a href="#compilers">What compilers are supported?</a></li>
	32	<li><a href="#bestcompiler">Which is the best compiler to use with wxWidgets?</a></li>
	33	<li><a href="#unicode">Is Unicode supported?</a></li>
	34	<li><a href="#doublebyte">Does wxWidgets support double byte fonts (Chinese/Japanese/Korean etc.)?</a></li>
	35	<li><a href="#dll">Can you compile wxWidgets as a DLL?</a></li>
	36	<li><a href="#exesize">How can I reduce executable size?</a></li>
	37	<li><a href="#mfc">Is wxWidgets compatible with MFC?</a></li>
	38	<li><a href="#setuph">Why do I get errors about setup.h not being found?</a></li>
	39	<li><a href="#asuffix">Why do I get errors about FooBarA when I only use FooBar in my program?</a></li>
	40	<li><a href="#newerrors">Why my code fails to compile with strange errors about new operator?</a></li>
	41	<li><a href="#mfcport">How do I port MFC applications to wxWidgets?</a></li>
	42	<li><a href="#crash">Why do I sometimes get bizarre crash problems using VC++ 5/6?</a></li>
	43	<li><a href="#makefiles">How are the wxWidgets makefiles edited under Windows?</a></li>
	44	<li><a href="#vcdebug">How do you use VC++'s memory leak checking instead of that in wxWidgets?</a></li>
	45	<li><a href="#shortcutproblem">Why are menu hotkeys or shortcuts not working in my application?</a></li>
	46	<li><a href="#regconfig">Why can I not write to the HKLM part of the registry with wxRegConfig?</a></li>
	47	<li><a href="#access">Is MS Active Accessibility supported?</a></li>
	48	<li><a href="#dspfmt">Why does Visual C++ complain about corrupted project files?</a></li>
	49	<li><a href="#crtmismatch">Visual C++ gives errors about multiply defined symbols, what can I do?</a></li>
	50	<li><a href="#directx">Why do I get compilation errors when using wxWidgets with DirectShow?</a></li>
	51	<li><a href="#handlewm">How do I handle Windows messages in my wxWidgets program?</a></li>
	52	</ul>
	53	<hr>
	54
	55	<h3><a name="platforms">Which Windows platforms are supported?</a></h3>
	56
	57	wxWidgets can be used to develop and deliver applications on Windows 95, Windows 98, Windows NT,
	58	Windows 2000, Windows XP, and Windows Vista. A Windows CE
	59	port is also available (see below).<P>
	60
	61	16-bit compilation is only supported for wxWidgets 2.4 and previous versions,
	62	using Visual C++ 1.5 and Borland BC++ 4 to 5.
	63	<P>
	64
	65	wxWidgets for Windows will also compile on Unix with gcc using Wine from <a href="http://www.winehq.org" target=_top>WineHQ</a>.
	66	The resulting executables are Unix binaries that work with the Wine Windows API emulator.<P>
	67
	68	You can also compile wxWidgets for Windows on Unix with Cygwin or Mingw32, resulting
	69	in executables that will run on Windows. So in theory you could write your applications
	70	using wxGTK or wxMotif, then check/debug your wxWidgets for Windows
	71	programs with Wine, and finally produce an ix86 Windows executable using Cygwin/Mingw32,
	72	without ever needing a copy of Microsoft Windows. See the Technical Note on the Web site detailing cross-compilation.<P>
	73
	74	<h3><a name="wince">What about Windows CE?</a></h3>
	75
	76	This port supports Pocket PC 2002/2003 and MS Smartphone 2002/2003, using
	77	Embedded Visual C++ 3 or 4. For further information, see the wxMSW section in
	78	the wxWidgets Reference Manual, and also the <a href="http://www.wxwidgets.org/embedded.htm#wxwince">wxEmbedded</a> page.<P>
	79
	80	<h3><a name="winxp">What do I need to do for Windows XP?</a></h3>
	81
	82	From wxWidgets 2.5, the XP manifest is included in wx/msw/wx.rc and
	83	so your application will be themed automatically so long as you include wx.rc
	84	in your own .rc file.<P>
	85
	86	For versions of wxWidgets below 2.5, you need to provide the manifest
	87	explicitly, as follows.<p>
	88
	89	In the same directory as you have your executable (e.g. foo.exe) you
	90	put a file called foo.exe.manifest in which you have something like
	91	the following:
	92
	93	<pre>
	94	<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
	95	<assembly
	96	xmlns="urn:schemas-microsoft-com:asm.v1"
	97	manifestVersion="1.0">
	98	<assemblyIdentity
	99	processorArchitecture="x86"
	100	version="5.1.0.0"
	101	type="win32"
	102	name="foo.exe"/>
	103	<description>Foo program</description>
	104	<dependency>
	105	<dependentAssembly>
	106	<assemblyIdentity
	107	type="win32"
	108	name="Microsoft.Windows.Common-Controls"
	109	version="6.0.0.0"
	110	publicKeyToken="6595b64144ccf1df"
	111	language="*"
	112	processorArchitecture="x86"/>
	113	</dependentAssembly>
	114	</dependency>
	115	</assembly>
	116	</pre>
	117
	118	If you want to add it to your application permanently,
	119	you can also include it in your .rc file using this
	120	line:<P>
	121
	122	<PRE>
	123	1 24 "winxp.manifest"
	124	</PRE>
	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 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?</a></h3>
	150
	151	It's partly a matter of taste, but some people prefer Visual C++ since the debugger is very
	152	good, it's very stable, the documentation is extensive, and it generates small executables.
	153	Since project files are plain text, it'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's hard (impossible?) to use the debugger without using project files, and
	157	the debugger is nowhere near up to VC++'s quality. The IDE isn't great.<P>
	158
	159	C++Builder's power isn't really used with wxWidgets since it needs integration with its
	160	own class library (VCL). For wxWidgets, I've only used it with makefiles, in which case
	161	it's almost identical to BC++ 5.0 (the same makefiles can be used).<P>
	162
	163	You can't beat Cygwin's price (free), and you can debug adequately using gdb. However, it'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'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. However BC++ has trouble compiling large executables statically,
	174	so you need to dynamically link the wxWidgets libraries.<p>
	175
	176	<h3><a name="unicode">Is Unicode supported?</a></h3>
	177
	178	Yes, Unicode is fully supported under Windows NT/2000 and there is limited
	179	support for it under Windows 9x using <a
	180	href="http://www.microsoft.com/globaldev/handson/dev/mslu_announce.mspx">MSLU</a>.
	181	<p>
	182
	183	<h3><a name="doublebyte">Does wxWidgets support double byte fonts (Chinese/Japanese/Korean etc.)?</a></h3>
	184
	185	For Japanese under Win2000, it seems that wxWidgets has no problems working
	186	with double byte char sets (meaning DBCS, not Unicode). First you have to
	187	install Japanese support on your Win2K system and choose for ANSI translation
	188	<tt>HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\CodePage=932</tt>
	189	(default is 1252 for Western). Then you can see all the Japanese letters in
	190	wxWidgets applications.
	191	<p>
	192
	193	<h3><a name="dll">Can you compile wxWidgets as a DLL?</a></h3>
	194
	195	Yes (using the Visual C++ or Borland C++ makefile), but be aware that distributing DLLs is a thorny issue
	196	and you may be better off compiling statically-linked applications, unless you're
	197	delivering a suite of separate programs, or you're compiling a lot of wxWidgets applications
	198	and have limited hard disk space.<P>
	199
	200	With a DLL approach, and with different versions and configurations of wxWidgets
	201	needing to be catered for, the end user may end up with a host of large DLLs in his or her Windows system directory,
	202	negating the point of using DLLs. Of course, this is not a problem just associated with
	203	wxWidgets!
	204	<P>
	205
	206	<h3><a name="exesize">How can I reduce executable size?</a></h3>
	207
	208	You can compile wxWidgets as a DLL (see above, VC++/BC++ only at present). You should also
	209	compile your programs for release using non-debugging and space-optimisation options, but
	210	take with VC++ 5/6 space optimisation: it can sometimes cause problems.<P>
	211
	212	If you want to distribute really small executables, you can
	213	use <a href="http://www.un4seen.com/petite/" target=_top>Petite</a>
	214	by Ian Luck. This nifty utility compresses Windows executables by around 50%, so your 500KB executable
	215	will shrink to a mere 250KB. With this sort of size, there is reduced incentive to
	216	use DLLs. Another good compression tool (probably better than Petite) is <a href="http://upx.sourceforge.net/" target=_top>UPX</a>.
	217	<P>
	218
	219	Please do not be surprised if MinGW produces a statically-linked minimal executable of 1 MB. Firstly, gcc
	220	produces larger executables than some compilers. Secondly, this figure will
	221	include most of the overhead of wxWidgets, so as your application becomes more
	222	complex, the overhead becomes proportionally less significant. And thirdly, trading executable compactness
	223	for the enormous increase in productivity you get with wxWidgets is almost always well worth it.<P>
	224
	225	If you have a really large executable compiled with MinGW (for example 20MB) then
	226	you need to configure wxWidgets to compile without debugging information: see
	227	docs/msw/install.txt for details. You may find that using configure instead
	228	of makefile.g95 is easier, particularly since you can maintain debug and
	229	release versions of the library simultaneously, in different directories.
	230	Also, run 'strip' after linking to remove all traces of debug info.
	231	<P>
	232
	233	<H3><a name="mfc">Is wxWidgets compatible with MFC?</a></H3>
	234
	235	There is a sample which demonstrates MFC and wxWidgets code co-existing in the same
	236	application. However, don't expect to be able to enable wxWidgets windows with OLE-2
	237	functionality using MFC.<P>
	238
	239	<H3><a name="setuph">Why do I get errors about setup.h not being found?</a></H3>
	240
	241	When you build the wxWidgets library, setup.h is copied
	242	from include/wx/msw/setup.h to e.g. lib/vc_msw/mswd/wx/setup.h (the path
	243	depends on the configuration you're building). So you need to add
	244	this include path if building using the static Debug library:<P>
	245
	246	lib/vc_lib/mswd<P>
	247
	248	or if building the static Release library, lib/vc_lib/msw.<P>
	249
	250	See also the <a href="http://wiki.wxwidgets.org/wiki.pl?Table_Of_Contents">wxWiki Contents</a>
	251	for more information.<P>
	252
	253
	254	<H3><a name="asuffix">Why do I get errors about FooBarA when I only use FooBar in my program?</H3>
	255
	256	If you get errors like
	257	<p>
	258	<center>
	259	<tt>no matching function for call to 'wxDC::DrawTextA(const char[5], int,
	260	int)'</tt>
	261	</center>
	262	<p>
	263	or similar ones for the other functions, i.e. the compiler error messages
	264	mention the function with the <tt>'A'</tt> suffix while you didn't
	265	use it in your code, the explanation is that you had included
	266	<tt><windows.h></tt> header which redefines many symbols to have such
	267	suffix (or <tt>'W'</tt> in the Unicode builds).
	268
	269	<p>
	270	The fix is to either not include <tt><windows.h></tt> at all or include
	271	<tt>"wx/msw/winundef.h"</tt> immediately after it.
	272
	273	<H3><a name="newerrors">Why my code fails to compile with strange errors about new operator?</a></H3>
	274
	275	The most common cause of this problem is the memory debugging settings in
	276	<tt>wx/msw/setup.h</tt>. You have several choices:
	277
	278	<ul>
	279	<li> Either disable overloading the global operator new completely by
	280	setting <tt>wxUSE_GLOBAL_MEMORY_OPERATORS</tt> and
	281	<tt>wxUSE_DEBUG_NEW_ALWAYS</tt> to 0 in this file
	282	<li> Or leave them on but do <tt>#undef new</tt> after including any
	283	wxWidgets headers, like this the memory debugging will be still on
	284	for wxWidgets sources but off for your own code
	285	</ul>
	286
	287	Notice that IMHO the first solution is preferable for VC++ users who can use
	288	the <a href="#vcdebug">VC++ CRT memory debugging features</a> instead.
	289
	290	<H3><a name="mfcport">How do I port MFC applications to wxWidgets?</a></H3>
	291
	292	Set up your interface from scratch using wxWidgets (especially <a href="http://www.robeling.de" target=_top>wxDesigner</a>
	293	or <a href="http://www.anthemion.co.uk/dialogblocks/" target=_new>DialogBlocks</a> --
	294	it'll save you a <i>lot</i> of time) and when you have a shell prepared, you can start
	295	'pouring in' code from the MFC app, with appropriate
	296	modifications. This is the approach I have used, and I found
	297	it very satisfactory. A two-step process then - reproduce the bare
	298	interface first, then wire it up afterwards. That way you deal
	299	with each area of complexity separately. Don't try to think MFC
	300	and wxWidgets simultaneously from the beginning - it is easier to
	301	reproduce the initial UI by looking at the behaviour of the MFC
	302	app, not its code.
	303
	304	<H3><a name="crash">Why do I sometimes get bizarre crash problems using VC++ 5/6?</a></H3>
	305
	306	Some crash problems can be due to inconsistent compiler
	307	options (and of course this isn't limited to wxWidgets).
	308	If strange/weird/impossible things start to happen please
	309	check (dumping IDE project file as makefile and doing text comparison
	310	if necessary) that the project settings, especially the list of defined
	311	symbols, struct packing, etc. are exactly the same for all items in
	312	the project. After this, delete everything (including PCH) and recompile.<P>
	313
	314	VC++ 5's optimization code seems to be broken and can
	315	cause problems: this can be seen when deleting an object Dialog
	316	Editor, in Release mode with optimizations on. If in doubt,
	317	switch off optimisations, although this will result in much
	318	larger executables. It seems possible that the library can be created with
	319	strong optimization, so long as the application is not strongly
	320	optimized. For example, in wxWidgets project, set to 'Minimum
	321	Size'. In Dialog Editor project, set to 'Customize: Favor Small
	322	Code' (and no others). This will then work.<P>
	323
	324	<H3><a name="makefiles">How are the wxWidgets makefiles edited under Windows?</a></H3>
	325
	326	wxWidgets 2.5.x and above uses Bakefile to generate makefiles, which
	327	is described in technical note 16 under docs/tech in your distribution.<p>
	328
	329	For 2.4.x, there is a system written by Vadim Zeitlin that
	330	generates the makefiles from templates using tmake.<P>
	331
	332	Here are Vadim's notes on tmake:<P>
	333
	334	<blockquote>
	335	To use these new makefiles, you don't need anything (but see below).
	336	However, you should NOT modify them because these files will be
	337	rewritten when I regenerate them using tmake the next time. So, if
	338	you find a problem with any of these makefiles (say, makefile.b32)
	339	you'll need to modify the corresponding template (b32.t in this
	340	example) and regenerate the makefile using tmake.<P>
	341
	342	tmake can be found at
	343	<a href="http://www.troll.no/freebies/tmake.html" target=_new>www.troll.no/freebies/tmake.html</a>.
	344	It's a Perl5 program and so it needs Perl (doh). There is a binary for
	345	Windows (available from the same page), but I haven't used it, so
	346	I don't know if it works as flawlessly as "perl tmake" does (note
	347	for people knowing Perl: don't try to run tmake with -w, it won't
	348	do you any good). Using it extremely simple: to regenerate makefile.b32
	349	just go to distrib/msw/tmake and type<P>
	350
	351	<pre>tmake -t b32 wxwin.pro -o ../../src/msw/makefile.b32</pre><P>
	352
	353	The makefiles are untested - I don't have any of Borland, Watcom or
	354	Symantec and I don't have enough diskspace to recompile even with
	355	VC6 using makefiles. The new makefiles are as close as possible to the
	356	old ones, but not closer: in fact, there has been many strange things
	357	(should I say bugs?) in some of makefiles, some files were not compiled
	358	without any reason etc. Please test them and notify me about any problems.
	359	Better yet, modify the template files to generate the correct makefiles
	360	and check them in.<P>
	361
	362	The templates are described in tmake ref manual (1-2 pages of text)
	363	and are quite simple. They do contain some Perl code, but my Perl is
	364	primitive (very C like) so it should be possible for anybody to make
	365	trivial modifications to it (I hope that only trivial modifications
	366	will be needed). I've tagged the ol makefiles as MAKEFILES_WITHOUT_TMAKE
	367	in the cvs, so you can always retrieve them and compare the new ones,
	368	this will make it easier to solve the problems you might have.<P>
	369
	370	Another important file is filelist.txt: it contains the list of all
	371	files to be compiled. Some of them are only compiled in 16/32 bit mode.
	372	Some other are only compiled with some compilers (others can't compile
	373	them) - all this info is contained in this file.<P>
	374
	375	So now adding a new file to wxWidgets is as easy as modifying filelist.txt
	376	(and Makefile.ams for Unix ports) and regenerating the makefiles - no
	377	need to modify all files manually any more.<P>
	378
	379	Finally, there is also a file vc6.t which I use myself: this one
	380	generates a project file for VC++ 6.0 (I didn't create vc5.t because
	381	I don't need it and can't test it, but it should be trivial to create
	382	one from vc6.t - probably the only things to change would be the
	383	version number in the very beginning and the /Z option - VC5 doesn't
	384	support edit-and=continue). This is not an officially supported way
	385	of building wxWidgets (that is, nobody guarantees that it will work),
	386	but it has been very useful to me and I hope it will be also for
	387	others. To generate wxWidgets.dsp run<P>
	388
	389	<pre>tmake -t vc6 wxwin.pro -o ../../wxWidgets.dsp</pre><P>
	390
	391	Then just include this project in any workspace or open it from VC IDE
	392	and it will create a new workspace for you.<P>
	393
	394	If all goes well, I'm planning to create a template file for Makefile.ams
	395	under src/gtk and src/motif and also replace all makefiles in the samples
	396	subdirectories with the project files from which all the others will be
	397	generated. At least it will divide the number of files in samples
	398	directory by 10 (and the number of files to be maintained too).
	399	</blockquote>
	400
	401	<P>
	402
	403	<H3><a name="vcdebug">How do you use VC++'s memory leak checking instead of that in wxWidgets?</a></H3>
	404
	405	Vadim Zeitlin:
	406
	407	<pre>
	408	On the VC++ level, it's just the matter of calling _CrtSetDbgFlag() in the very
	409	beginning of the program. In wxWidgets, this is done automatically when
	410	compiling with VC++ in debug mode unless wxUSE_GLOBAL_MEMORY_OPERATORS or
	411	__NO_VC_CRTDBG__ are defined - this check is done in wx/msw/msvcrt.h which
	412	is included from app.cpp which then calls wxCrtSetDbgFlag() without any
	413	ifdefs.
	414
	415	This works quite well: at the end of the program, all leaked blocks with their
	416	malloc count are shown. This number (malloc count) can be used to determine
	417	where exactly the object was allocated: for this it's enough to set the variable
	418	_crtBreakAlloc (look in VC98\crt\srs\dbgheap.c line 326) to this number and
	419	a breakpoint will be triggered when the block with this number is allocated.
	420
	421	For simple situations it works like a charm. For something more complicated
	422	like reading uninitialized memory a specialized tool is probably better...
	423
	424	Regards,
	425	VZ
	426	</pre>
	427
	428	<P>
	429
	430	<H3><a name="shortcutproblem">Why are menu hotkeys or shortcuts not working in my application?</a></H3>
	431
	432	This can happen if you have a child window intercepting EVT_CHAR events and swallowing
	433	all keyboard input. You should ensure that event.Skip() is called for all input that
	434	isn'used by the event handler.<P>
	435
	436	It can also happen if you append the submenu to the parent
	437	menu {\it before} you have added your menu items. Do the append {\it after} adding
	438	your items, or accelerators may not be registered properly.<P>
	439
	440	<H3><a name="#regconfig">Why can I not write to the HKLM part of the registry with wxRegConfig?</a></H3>
	441
	442	Currently this is not possible because the wxConfig family of classes is
	443	supposed to deal with per-user application configuration data, and HKLM is
	444	only supposed to be writeable by a user with Administrator privileges. In theory,
	445	only installers should write to HKLM. This is still a point debated by the
	446	wxWidgets developers. There are at least two ways to work around it if you really
	447	need to write to HKLM.<P>
	448
	449	First, you can use wxRegKey directly, for example:
	450
	451	<pre>
	452	wxRegKey regKey;
	453
	454	wxString idName(wxT("HKEY_LOCAL_MACHINE\\SOFTWARE\\My Company\\My Product\\Stuff\\"));
	455	idName += packid;
	456
	457	regKey.SetName(idName);
	458
	459	{
	460	wxLogNull dummy;
	461	if (!regKey.Create())
	462	{
	463	idName = wxT("HKEY_CURRENT_USER\\SOFTWARE\\My Company\\My Product\\Stuff\\");
	464	idName += packid;
	465	regKey.SetName(idName);
	466	if (!regKey.Create())
	467	return FALSE;
	468	}
	469	}
	470
	471	if (!regKey.SetValue(wxT("THING"), (long) thing)) err += 1;
	472
	473	regKey.Close();
	474
	475	</pre>
	476
	477	Or, you can employ this trick suggested by Istvan Kovacs:
	478
	479	<pre>
	480	class myGlobalConfig : public wxConfig
	481	{
	482	myGlobalConfig() :
	483	wxConfig ("myApp", "myCompany", "", "", wxCONFIG_USE_GLOBAL_FILE)
	484	{};
	485	bool Write(const wxString& key, const wxString& value);
	486	}
	487
	488	bool myGlobalConfig::Write (const wxString& key, const wxString& value)
	489	{
	490	wxString path = wxString ("SOFTWARE\\myCompany\\myApp\\") + wxPathOnly(key);
	491	wxString new_path = path.Replace ("/", "\\", true);
	492	wxString new_key = wxFileNameFromPath (key);
	493	LocalKey().SetName (wxRegKey::HKLM, path);
	494	return wxConfig::Write (new_key, value);
	495	}
	496	</pre>
	497
	498	<H3><a name="#access">Is MS Active Accessibility supported?</a></H3>
	499
	500	This is being worked on. Please see <a href="http://www.wxwidgets.org/access.htm">this page</a>
	501	for the current status.
	502
	503	<P>
	504
	505
	506	<h3><a name="#dspfmt">Why does Visual C++ complain about corrupted project files?</a></h3>
	507
	508	If you have downloaded the wxWidgets sources from the cvs using a Unix cvs
	509	client or downloaded a daily snapshot in <tt>.tar.gz</tt> format, it is likely
	510	that the project files have Unix line endings (LF) instead of the DOS ones (CR
	511	LF). However all versions of Visual C++ up to and including 7.1 can only open
	512	the files with the DOS line endings, so you must transform the files to this
	513	format using any of the thousands ways to do it.
	514	<p>
	515	Of course, another possibility is to always use only the Windows cvs client
	516	and to avoid this problem completely.
	517	<p>
	518
	519	<h3><a name="#crtmismatch">Visual C++ gives errors about multiply defined symbols, what can I do?</a></h3>
	520
	521	If you get errors like this
	522
	523	<pre>
	524	MSVCRTD.lib(MSVCRTD.dll) : error LNK2005: _xxxxxx already defined in LIBCD.lib(yyyyy.obj)
	525	</pre>
	526
	527	when linking your project, this means that you used different versions of CRT
	528	(C Run-Time) library for wxWindows (or possibly another library) and the main
	529	project. Visual C++ provides static or dynamic and multithread safe or not
	530	versions of CRT for each of debug and release builds, for a total of 8
	531	libraries. You can choose among them by going to the "Code generation"
	532	page/subitem of the "C++" tab/item in the project proprieties dialog in VC6/7.
	533	<p>
	534	To avoid problems, you <strong>must</strong> use the same one for all
	535	components of your project. wxWindows uses multithread safe DLL version of the
	536	CRT which is a good choice but may be problematic when distributing your
	537	applications if you don't include the CRT DLL in your installation -- in this
	538	case you may decide to switch to using a static CRT version. If you build with
	539	<tt>wxUSE_THREADS == 0</tt> you may also use the non MT-safe version as it is
	540	slightly smaller and faster.
	541	<p>
	542	But the most important thing is to use the <strong>same</strong> CRT setting for
	543	all components of your project.
	544
	545	<h3><a name="#directx">Why do I get compilation errors when using wxWidgets with DirectShow?</a></h3>
	546
	547	If you get errors when including Microsoft DirectShow or DirectDraw headers,
	548	the following message from Peter Whaite could help:
	549	<blockquote>
	550	> This causes compilation errors within DirectShow:
	551	>
	552	> wxutil.h(125) : error C2065: 'EXECUTE_ASSERT' : undeclared identifier
	553	> amfilter.h(1099) : error C2065: 'ASSERT' : undeclared identifier
	554
	555	The reason for this is that __WXDEBUG__ is also used by the DXSDK (9.0
	556	in my case) to '#pragma once' the contents of
	557	DXSDK/Samples/C++/DirectShow/BaseClasses/wxdebug.h. So if __WXDEBUG__
	558	is defined, then wxdebug.h doesn't get included, and the assert macros
	559	don't get defined. You have to #undef __WXDEBUG__ before including the
	560	directshow baseclass's <streams.h>.
	561	</blockquote>
	562
	563
	564	<h3><a name="#handlewm">How do I handle Windows messages in my wxWidgets program?</a></h3>
	565
	566	To handle a Windows message you need to override a virtual
	567	<tt>MSWWindowProc()</tt> method in a wxWindow-derived class. You should then
	568	test if <tt>nMsg</tt> parameter is the message you need to process and perform
	569	the necessary action if it is or call the base class method otherwise.
	570
	571
	572	</font>
	573
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	575
	576	</HTML>