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   5 <TITLE>wxWidgets 2 FAQ: General</TITLE>
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  16 <b>wxWidgets 2 FAQ: General</b>
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  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="#whatis">What is wxWidgets?</a></li>
  29 <li><a href="#licence">Can I use wxWidgets 2 for both proprietary projects, and GPL&#39;ed projects?</a></li>
  30 <li><a href="#support">Is there support?</a></li>
  31 <li><a href="#users">Who uses wxWidgets?</a></li>
  32 <li><a href="#platforms">What platforms are supported by wxWidgets?</a></li>
  33 <li><a href="#specific">How does wxWidgets support platform-specific features?</a></li>
  34 <li><a href="#stl">Does wxWidgets use STL? or the standard string class?</a></li>
  35 <li><a href="#richedit">Is there a rich edit/markup widget for wxWidgets?</a></ li>
  36 <li><a href="#exceptions">How to use C++ exceptions with wxWidgets?</a></ li>
  37 <li><a href="#dev">How is wxWidgets being developed?</a></li>
  38 <li><a href="#distrib">How is wxWidgets distributed?</a></li>
  39 <li><a href="#future">What are the plans for the future?</a></li>
  40 <li><a href="#base">What is wxBase?</a></li>
  41 <li><a href="#univ">What is wxUniversal?</a></li>
  42 <li><a href="#jave">What about Java?</a></li>
  43 <li><a href="#dotnet">What about .NET/Mono?</a></li>
  44 <li><a href="#help">How can I help the project?</a></li>
  45 <li><a href="#newport">How do I start a new port?</a></li>
  46 </ul>
  47 <hr>
  48
  49 <H3><a name="whatis">What is wxWidgets?</a></H3>
  50
  51 wxWidgets is a class library that allows you to compile graphical C++ programs on a range of
  52 different platforms. wxWidgets defines a common API across platforms, but uses the native graphical user interface (GUI) on each platform,
  53 so your program will take on the native &#39;look and feel&#39; that users are familiar with.<P>
  54
  55 Although GUI applications are mostly built programmatically, there are several dialog editors to help
  56 build attractive dialogs and panels. Robert Roebling&#39;s <a href="http://www.roebling.com">wxDesigner</a>
  57 and Anthemion Software's <a href="http://www.anthemion.co.uk/dialogblocks/" target=_new>DialogBlocks</a>
  58 are two commercial examples, but there are others: see the <a href="lnk_tool.htm">Useful Tools</a> page.<P>
  59
  60 You don&#39;t have to use C++ to use wxWidgets: there is a <a href="http://wxpython.org">Python interface</a> for wxWidgets 2,
  61 and also a <a href="http://wxperl.sourceforge.net" target=_top>Perl interface</a>.
  62 <P>
  63
  64 <h3><a name="licence">Can I use wxWidgets 2 for both proprietary (commercial) projects, and GPL&#39;ed projects?</a></h3>
  65
  66 Yes. Please see the <a href="newlicen.htm">licence</a> for details, but basically
  67 you can distribute proprietary binaries without distributing any source code, and neither will wxWidgets
  68 conflict with GPL code you may be using or developing with it.
  69 <P>
  70 The conditions for using wxWidgets 2 are the same whether you are a personal, academic
  71 or commercial developer.
  72 <P>
  73
  74 <h3><a name="support">Is there support?</a></h3>
  75
  76 No official support, but the mailing list is very helpful and some people say that
  77 wxWidgets support is better than for much commercial software. The developers are
  78 keen to fix bugs as soon as possible, though obviously there are no guarantees.
  79 <P>
  80
  81 <H3><a name="users">Who uses wxWidgets?</a></H3>
  82
  83 Many organisations - commercial, government, and academic - across the
  84 world. It&#39;s impossible to estimate the true number of users, since
  85 wxWidgets is obtained by many different means, and we cannot monitor
  86 distribution. The mailing list contains around 300-400 entries which is
  87 quite large for a list of this type.<P>
  88
  89 See <a href="users.htm">Users</a> for a list of some users and their applications, and
  90 also <A href="feedback.htm">Feedback</a> for comments.<P>
  91 Our highest-profile user yet is industry veteran and Lotus Corp. founder Mitch Kapor
  92 and his <a href="http://www.osafoundation.org" target=_new>Open Source Applications Foundation</a>.
  93 <P>
  94
  95 <H3><a name="platforms">What platforms are supported by wxWidgets 2?</a></H3>
  96
  97 <ul>
  98 <li>Windows 3.1, Windows 95/98, Windows NT, Windows 2000, Windows ME.
  99 <li>Linux and other Unix platforms with GTK+.
 100 <li>Unix with Motif or the free Motif clone Lesstif.
 101 <li>Mac OS.
 102 <li>Embedded platforms are being investigated. See the <a href="wxuniv.htm">wxUniversal</a> project.
 103 <li>An OS/2 port is in progress, and you can also compile wxWidgets for GTK+ or Motif
 104 on OS/2.
 105 </ul>
 106 <P>
 107
 108 <H3><a name="specific">How does wxWidgets 2 support platform-specific
 109 features?</a></H3>
 110
 111 This is a hotly-debated topic amongst the developers. My own philosophy
 112 is to make wxWidgets as platform-independent as possible, but allow in a
 113 few classes (functions, window styles) that are platform-specific.
 114 For example, Windows metafiles and Windows 95 taskbar icons have
 115 their own classes on Windows, but nowhere else. Because these classes
 116 are provided and are wxWidgets-compatible, it doesn&#39;t take much
 117 coding effort for an application programmer to add support for
 118 some functionality that the user on a particular platform might otherwise
 119 miss. Also, some classes that started off as platform-specific, such
 120 as the MDI classes, have been emulated on other platforms. I can imagine
 121 that even wxTaskBarIcon may be implemented for Unix desktops one day.
 122 <P>
 123
 124 In other words, wxWidgets is not a &#39;lowest common denominator&#39; approach,
 125 but it will still be possible to write portable programs using the
 126 core API. Forbidding some platform-specific classes would be a stupid
 127 approach that would alienate many potential users, and encourage
 128 the perception that toolkits such as wxWidgets are not up to the demands
 129 of today&#39;s sophisticated applications.<P>
 130
 131 Currently resources such as bitmaps and icons are handled in a platform-specific
 132 way, but it is hoped to reduce this dependence in due course.<P>
 133
 134 Another reason why wxWidgets 2 is not a &#39;lowest common denominator&#39; toolkit is that
 135 some functionality missing on some platform has been provided using generic,
 136 platform-independent code, such as the wxTreeCtrl and wxListCtrl classes.<P>
 137
 138 <H3><a name="stl">Does wxWidgets use STL? or the standard string class?</a></H3>
 139
 140 No. This is a much-discussed topic that has (many times) ended with the conclusion that it is in
 141 wxWidgets&#39; best interests to avoid use of templates. Not all compilers can handle
 142 templates adequately so it would dramatically reduce the number of compilers
 143 and platforms that could be supported. It would also be undesirable to make
 144 wxWidgets dependent on another large library that may have to be downloaded and installed.
 145 In addition, use of templates can lead to executable bloat, which is something
 146 wxWidgets 2 is strenuously trying to avoid.<P>
 147
 148 The standard C++ string class is not used, again because it is not available to all compilers,
 149 and it is not necessarily a very efficient implementation. Also, we retain more flexibility
 150 by being able to modify our own string class. Some compatibility with the string class
 151 has been built into wxString.<P>
 152
 153 There is nothing to stop an application using templates or the string class for its own
 154 purposes. With wxWidgets debugging options on, you may find you get errors when including
 155 STL headers. You can work around it either by switching off memory checking,
 156 or by adding this to a header before you include any STL files:<P>
 157
 158 <PRE>
 159 &#35;ifdef new
 160 &#35;undef new
 161 &#35;endif
 162 </PRE>
 163
 164 <P>
 165
 166
 167 <H3><a name="richedit">Is there a rich edit/markup widget for wxWidgets 2?</a></H3>
 168
 169 These are the possibilities so far:<P>
 170
 171 <ul>
 172 <li>See <a href="http://www.scintilla.org" target=_top>www.scintilla.org</a> for
 173 a very nice syntax-highlighting editor widget. Robin Dunn has written a wxWidgets wrapper
 174 for this widget, available in the wxWidgets distribution under contrib/src/stc.
 175 <li>If you only need to display marked-up information, rather than edit it,
 176 then wxHTML will suit your needs. wxHTML is built into wxWidgets - please see the reference
 177 manual for details, and samples/html.
 178 <li>There are rich edit widgets in both WIN32 and GTK+, but there is currently
 179 no wxWidgets wrapper for these (but text attribute functions are being added in the wxWidgets 2.3.x series).
 180 </ul>
 181
 182 <P>
 183
 184 <h3><a name="exceptions">How to use C++ exceptions with wxWidgets?</a></h3>
 185
 186 wxWidgets library itself is unfortunately <i>not</i> exception-safe (as its
 187 initial version predates, by far, the addition of the exceptions to the C++
 188 language). However you can still use the exceptions in your own code and use
 189 the other libraries using the exceptions for the error reporting together with
 190 wxWidgets.
 191
 192 <p>
 193 There are a few issues to keep in mind, though:
 194 <ul>
 195     <li>You shouldn&#39;t let the exceptions propagate through wxWidgets code,
 196         in particular you should always catch the exceptions thrown by the
 197         functions called from an event handler in the handler itself and not
 198         let them propagate upwards to wxWidgets.
 199
 200     <li>You may need to ensure that the compiler support for the exceptions is
 201         enabled as, considering that wxWidgets itself doesn&#39;t use the
 202         exceptions and turning their support on results in the library size
 203         augmentation of 10% to 20%, it is turned off by default for a few
 204         compilers. Moreover, for gcc (or at least its mingw version) you must
 205         also turn on the RTTI support to be able to use the exceptions, so you
 206         should use <tt>--disable-no_rtti --disable-no_exceptions</tt> options
 207         when configuring the library (attention to the double negation).
 208 </ul>
 209
 210 <p>
 211
 212 <H3><a name="dev">How is wxWidgets being developed?</a></H3>
 213
 214 We are using the <a href="cvs.htm">CVS</a> system to develop and maintain wxWidgets. This allows
 215 us to make alterations and upload them instantly to the server, from
 216 which others can update their source.<P>
 217
 218 To build source from CVS, see the file BuildCVS.txt in the top-level wxWidgets distribution
 219 directory.<P>
 220
 221 <H3><a name="distrib">How is wxWidgets distributed?</a></H3>
 222
 223 By ftp, and via the <a href="cdrom2.htm">wxWidgets CD-ROM</a>.
 224 <P>
 225 If you are feeling adventurous, you may also check out the sources directly
 226 from <a href="cvs.htm">cvs</a>.
 227 <p>
 228
 229 <H3><a name="future">What are the plans for the future?</a></H3>
 230
 231 Currently we&#39;re working too hard on getting wxWidgets finished (are GUI toolkits ever
 232 finished?) to think very far ahead. However, we know we want to make wxWidgets as robust
 233 and well-publicised as possible. We also want to aim for better platform-independence of
 234 resources such as icons and bitmaps, standardising on PNG and XPM for all platforms.<P>
 235
 236 Other possibilities include: DCOM/CORBA compatibility; a wxWidgets book;
 237 <a href="http://wxworkshop.sourceforge.net/">wxWorkshop</a>, an IDE;
 238 other platforms, especially embedded systems; other interface abilities such as speech output.<P>
 239
 240 We will investigate the possibility of compiler or operating system vendors bundling wxWidgets with
 241 their product.<P>
 242
 243 The high-level goal of wxWidgets is to be thought of as the number one C++ framework,
 244 for virtually any platform. Move over, MFC!<P>
 245
 246 <h3><a name="base">What is wxBase?</a></h3>
 247
 248 wxBase is a subset of wxWidgets comprised by the non-GUI classes. It includes
 249 wxWidgets container and primitive data type classes (including wxString,
 250 wxDateTime and so on) and also useful wrappers for the operating system objects
 251 such as files, processes, threads, sockets and so on. With very minor
 252 exceptions wxBase may be used in exactly the same way as wxWidgets but it
 253 doesn&#39;t require a GUI to run and so is ideal for creating console mode
 254 utilities or server programs. It is also possible to create a program which can
 255 be compiled either as a console application (using wxBase) or a GUI one (using
 256 a full featured wxWidgets port).
 257
 258 <H3><a name="univ">What is wxUniversal?</a></H3>
 259
 260 The main difference between wxUniversal-based ports (such as wxX11, wxMGL) and other ports (such as wxMSW, wxGTK+, wxMac)
 261 is that wxUniversal implements all controls (or widgets) in
 262 wxWidgets itself thus allowing to have much more flexibility (for example, support for
 263 themes even under MS Windows). It also means that it is now much easier to
 264 port wxWidgets to a new platform as only the low-level classes must be ported
 265 which make for a small part of the library.
 266 <p>
 267 You may find more about wxUniversal <a href=wxuniv.htm>here</a>.
 268
 269 <H3><a name="jave">What about Java?</a></H3>
 270
 271 The Java honeymoon period is over :-) and people are realising that it cannot
 272 meet all their cross-platform development needs. We don&#39;t anticipate a major threat
 273 from Java, and the level of interest in wxWidgets is as high as ever.<P>
 274
 275 <H3><a name="dotnet">What about .NET/Mono?</a></H3>
 276
 277 Microsoft is spending a lot on promoting the .NET initiative, which
 278 is a set of languages, APIs and web service components for Windows.
 279 Ximian has started an open source version of .NET, mostly for Linux.
 280 C&#35; is Microsoft's alternative to Java, supporting 'managed code',
 281 garbage collection and various other Java-like language features.<P>
 282
 283 Although this may be attractive to some developers, there
 284 is a variety of reasons why the .NET/Mono combination is unlikely
 285 to make wxWidgets redundant. Please note that the following comments
 286 are Julian Smart's opinions.<P>
 287
 288 <ol>
 289 <li>Not everyone wants or needs net services.
 290 <li>C++ will be used for a long time to come; compared with C++, C&#35; is a recent development and its future is not certain.
 291 <li>Mono Forms may only target Winelib (at least to begin with), so the end result is not as native as
 292 wxWidgets (I'm aware there is GTK&#35; for use with the C&#35; language).
 293 <li>C&#35; is usually byte-compiled and therefore slower. Plus, .NET adds a layer of overhead to the client computer
 294 that wxWidgets does not require.
 295 <li>Mono hasn't proven its long-term viability yet (it's a complex system of components); wxWidgets is ready now.
 296 <li>You may not wish to buy into Microsoft marketing spin and APIs.
 297 <li>Microsoft may at some point sue developers of non-Microsoft .NET implementations. After all,
 298 platform-independence is not in Microsoft's interest.
 299 <li>.NET might never be implemented on some platforms, especially Mac and embedded variants of Linux.
 300 <li>wxPython and other language variants provide further reasons for wxWidgets to continue.
 301 <li>The same issue exists for Qt: if Qt sales remain strong, it's a good indication that
 302 the market for a C++-based approach is still there. (Either that, or everyone's turning to wxWidgets!)
 303 </ol>
 304
 305 There is nothing to stop folk from developing a C&#35; version of the wxWidgets API;
 306 we already have bindings to Python, Perl, JavaScript, Lua, Basic, and Eiffel.
 307 Update: a <a href="http://wxnet.sourceforge.net/" target=_new>wx.NET</a> project is now in progress.
 308
 309 <P>
 310
 311 <H3><a name="help">How can I help the project?</a></H3>
 312
 313 Please check out the <a href="http://www.wxwidgets.org/develop2.htm">Community</a> pages,
 314 in particular the <a href="projects.htm">suggested projects</a>, and
 315 mail the developers&#39; mailing list with your own suggestions.<P>
 316
 317 <H3><a name="newport">How do I start a new port?</a></H3>
 318
 319 Please subscribe to the wx-dev <a href="maillst2.htm">developers&#39; mailing list</a> and
 320 ask if anyone else is interested in helping with the port, or
 321 has specific suggestions. Also please read the <a href="standard.htm">coding standards</a>.
 322
 323 <P>
 324 Each port consists of a platform-specific part (e.g. src/msw, include/wx/msw),
 325 a generic set of widgets and dialogs for when the port doesn't support
 326 them natively (src/generic, include/wx/generic) and the common code
 327 that all ports use (src/common, include/wx). By browsing the source
 328 you should get a good idea of the general pattern.<P>
 329
 330 Take a port that most closely matches your port, and strip out
 331 the implementation so you have a skeleton port that compiles. Ask on wx-dev
 332 first for the wxStubs port - however, any such predefined skeleton
 333 port may be out of date, so make a judgement on whether to use it.
 334 Perhaps it will still save you time to clean up wxStubs, and
 335 others may benefit from this too.<P>
 336
 337 You will need to define a symbol for the new port, e.g. __WXXBOX__.
 338 Look at files such as wx/defs.h, wx/wxchar.h for areas where you'll
 339 need to add to existing conditionals to set up wide character
 340 support and other issues. If the GUI runs on a Unix variant,
 341 define the __UNIX__ variable in your makefile.<P>
 342
 343 Then you can start implementing the port, starting with
 344 wxWindow, wxTopLevelWindow, wxFrame, wxDialog so you
 345 can get the minimal sample running as soon as possible.<P>
 346
 347 If GDI objects (wxPen, wxBrush, etc.) are not concepts in your
 348 native GUI, you may wish to use very generic versions of
 349 some of these - see the wxX11 port.<P>
 350
 351 Consider using the wxUniversal widget set as a quick way
 352 to implement wxWidgets on your platform. You only need
 353 to define some basic classes such as device contexts,
 354 wxWindow, wxTopLevelWindow, GDI objects etc. and
 355 the actual widgets will be drawn for you. See wxX11,
 356 wxMGL, and wxMSW/Univ for sample wxUniversal ports.<P>
 357
 358 To begin with, you can use whatever makefiles or project
 359 files work for you. Look at existing makefiles to see what
 360 generic/common/Unix files need to be included. Later, you'll want to integrate support
 361 for your port into configure (Unix-like systems and gcc under Windows),
 362 and bakefile (for other makefiles on Windows).<P>
 363
 364 Submit your port as patches via SourceForge; you might
 365 wish to separate it into one patch that touches common headers
 366 and source files, and another containing the port-specific code, to make
 367 it much easier for us to review and apply the patches.<P>
 368
 369 Good luck!
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