1 <a href="#basics">Basics</a><br>
2 <a href="#ximian">The Ximian Role in the Mono project</a><br>
3 <a href="#gnome">Mono and GNOME</a><br>
4 <a href="#gui">Building GUI applications with Mono</a><br>
5 <a href="#msft">Mono and Microsoft</a><br>
6 <a href="#platforms">Mono platforms</a><br>
7 <a href="#compatibility">Compatibility</a></br>
8 <a href="#pnpproject">Mono and the Portable.NET Project</a><br>
9 <a href="#webservices">Web Services</a><br>
10 <a href="#asp">Mono and ASP.NET</a><br>
11 <a href="#ado">Mono and ADO.NET</a><br>
12 <a href="#monodoc">MonoDoc</a><br>
13 <a href="#devel">Development Tools and Issues</a><br>
14 <a href="#java">Mono and Java</a><br>
15 <a href="#extending">Extending Mono</a><br>
16 <a href="#portability">Portability</a><br>
17 <a href="#reuse">Reusing Existing Code</a><br>
18 <a href="#gcc">Mono and GCC</a><br>
19 <a href="#performance">Performance</a><br>
20 <a href="#licensing">Licensing</a><br>
21 <a href="#patents">Patents</a><br>
22 <a href="#etc">Miscellaneous Questions</a><br>
23 <a href="#problems">Mono Common Problems</a><br>
26 href="http://www.es.gnome.org/documentacion/articulos/mono-puf/mono-puf/">Spanish
27 translation</a> is also available
32 Q: What is Mono exactly?
34 A: The Mono Project is an open development initiative sponsored by
35 Ximian that is working to develop an open source, Unix
36 version of the Microsoft .NET development platform. Its objective
37 is to enable Unix developers to build and
38 deploy cross-platform .NET Applications. The project will
39 implement various technologies developed by Microsoft that have now
40 been submitted to the ECMA for standardization.
42 The Mono project has also sparked a lot of interest in developing
43 C#-based components, libraries and frameworks. Today Mono is not
44 limited to implement the .NET Framework, but also contains other
45 components. Some of the components of the Mono platform were
46 developed by the Mono team, and some others we have incorporated
47 from other open source efforts, the most important ones:
51 href="http://remoting-corba.sourceforge.net/">Remoting.CORBA</a>: A
52 CORBA implementation for Mono.
54 <li>Ginzu: An implementation on top of Remoting for the <a
55 href="http://www.zeroc.com">ICE</a> stack
57 <li><a href="http://gtk-sharp.sf.net">Gtk#</a>: Bindings for
58 the popular Gtk+ GUI toolkit for Unix and Windows systems.
59 Other bindings are available: Diacanvas-Sharp and MrProject.
62 href="http://www.icsharpcode.net/OpenSource/SharpZipLib/Default.aspx">#ZipLib</a>:
63 A library to manipulate various kinds of compressed files and
64 archives (Zip and tar).
66 <li>GlGen (available from the Mono CVS): Bindings for OpenGL.
68 <li>Mono.LDAP: LDAP access for .NET apps.
70 <li>Mono.Data: We ship support for Postgress, MySql, Sybase,
71 DB2, SqlLite, Tds (SQL server protocol) and Oracle databases.
73 <li>Mono.Cairo: Bindings for the <a
74 href="http://www.cairographics.org">Cairo</a> rendering
75 engine (Our System.Drawing is implemented on top of this).
77 <li>Mono.Posix: Bindings for building POSIX applications using
80 <li>Mono.Http: Support for creating custom, embedded HTTP
81 servers and common HTTP handlers for your applications.
84 Q: What is the difference between Mono and the .NET Initiative?
86 A: The ".NET Initiative" is a somewhat nebulous company-wide effort by
87 Microsoft, one part of which is a cross-platform development
88 framework. Mono is an implementation of the development framework,
89 but not an implementation of anything else related to the .NET
90 Initiative, such as Passport, software-as-a-service, or
91 corporate re-branding.
93 Q: What technologies are included in Mono?
95 A: Mono contains a number of components useful for building new
99 * A Common Language Infrastructure (CLI) virtual
100 machine that contains a class loader, Just-in-time
101 compiler, and a garbage collecting runtime.
103 * A class library that can work with any language
104 which works on the CLR. Both .NET compatible class
105 libraries as well as Mono-provided class libraries
108 * A compiler for the C# language. In the future we
109 might work on other compilers that target the Common
114 Windows has compilers that target the virtual machine from <a
115 href="http://msdn.microsoft.com/net/thirdparty/default.asp#lang">a
116 number of languages:</a> Managed C++, Java Script, Eiffel,
117 Component Pascal, APL, Cobol, Perl, Python, Scheme,
118 Smalltalk, Standard ML, Haskell, Mercury and Oberon.
120 The CLR and the Common Type System (CTS) enables applications and
121 libraries to be written in a collection of different languages that
124 This means for example that if you define a class to do algebraic
125 manipulation in C#, that class can be reused from any other
126 language that supports the CLI. You could create a class in C#,
127 subclass it in C++ and instantiate it in an Eiffel program.
129 A single object system, threading system, class libraries, and
130 garbage collection system can be shared across all these languages.
132 Q: Where can I find the specification for these technologies?
134 A: You can find the information here:
137 C# <a href="http://www.ecma.ch/ecma1/STAND/ecma-334.htm">http://www.ecma.ch/ecma1/STAND/ecma-334.htm</a>
139 CLI <a href="http://www.ecma.ch/ecma1/STAND/ecma-335.htm">http://www.ecma.ch/ecma1/STAND/ecma-335.htm</a>
141 Q: Will you implement the .NET Framework SDK class libraries?
143 A: Yes, we will be implementing the APIs of the .NET Framework SDK
146 Q: Will you offer an ECMA-compliant set of class libraries?
148 A: Eventually we will. Our current focus is on inter-operating
149 with the Microsoft SDK, but we will also offer an ECMA compliant
152 Q: What does the name "Mono" mean?
154 A: Mono is the word for `monkey' in Spanish. We like monkeys.
158 A: The JIT engine is usable on Intel x86 machines. An interpreter
159 can be used on other non-Intel x86 machines.
161 The class libraries are mature enough to run some real applications
162 (the compiler for instance, and every day more and more applications
163 are natively developed with Mono).
165 Q: When will you ship it?
167 A: Different parts of Mono will achieve usability at different stages,
168 once we are comfortable with the compiler, we will release "Mono Core",
169 which contains everything needed to develop applications with the base
170 class libraries, this will happen soon and in the meantime you can
171 download daily snapshots of our work. Also the full ASP.NET support is
174 Other higher level class libraries (ASP.NET, ADO.NET, WinForms) will
175 be released when they become stable.
177 Q: When will Mono 1.0 ship?
179 A: We are planning on releasing Mono 1.0 (Mono Core) which will ship all the
180 components of Mono that are known to be stable in Q4 2003/Q1 2004.
182 This release will lack System.Windows.Forms and
183 Enterprise.Services, as they will not be production ready on this timeframe.
185 Mono 1.2 should come in Q2 2004 and include the missing components
186 libraries that will make Mono feature-compatible with .NET 1.0
188 Q: What major components will you include in Mono?
190 A: Hopefully everything that Microsoft ships on their Framework
191 (ADO.NET, ASP.NET, WinForms), and we encourage third party developers to
192 create reusable components that work on both Mono and Windows.
194 Q: How can I contribute?
196 A: Check the <a href="contributing.html">contributing</a> section.
198 Q: Aren't you just copying someone else's work?
200 A: We are interested in providing the best tools for programmers to
201 develop applications for Free Operating Systems. We also want to help
202 provide the interoperability that will allow those systems to fit in
203 with other standards.
205 For more background, read the <a href="http://www.go-mono.com/rationale.html">Mono
206 Project white paper</a>.
209 Q: Miguel said once that Mono was being implemented in COBOL. Is that true?.
211 A: No. It was a joke.
214 <a name="ximian"></a>
216 ** The Ximian Role in the Mono Project
218 Q: Why is Ximian working on .NET?
220 A: Ximian is interested in providing the best tools for programmers to
221 develop applications for Free Operating Systems.
223 For more information, read the project <a
224 href="rationale.html">rationale</a> page.
226 Q: Will Ximian be able to take on a project of this size?
228 A: Of course not. Ximian a supporter of the Mono project, but the only way
229 to implement something of this size is for the entire free software
230 community to get involved. Visit the <a href="contributing.html">contributing</a>
231 page if you'd like to help out.
233 Q: What pieces will Ximian be working on?
235 A: We will devote most of our resources to work on the pieces which are
236 on the critical path to release a development and execution
237 environment. Once the project is at a stage where it is useful in
238 the real world, it will achieve a critical mass of developers to
241 Q: Will Ximian offer Mono commercially?
243 A: When Mono is ready to be shipped Ximian will offer a commercial
244 support and services for Mono.
246 Q: Does Ximian provide consulting services around Mono?
248 A: Yes, Ximian does provide consulting services around Mono to
249 make it suitable to your needs. Porting the runtime engine,
250 customizing it, working on specific classes or tuning the code
251 for your particular needs.
253 Q: Will you wait until Mono is finished?
255 A: Mono will ship on various stages as they mature. Some people
256 require only a subset of the technologies, those will ship first.
258 More advanced features will take more time to develop. A support
259 time line will be available in June 2002.
264 Q: How is Mono related to GNOME?
266 A: In a number of ways. This project was born out of the need of
267 providing improved tools for the GNOME community, and will use
268 existing components that have been developed for GNOME when they
269 are available. For example, we plan to use Gtk+ and Libart to
270 implement Winforms and the Drawing2D API and are considering
273 Q: Has the GNOME Foundation or the GNOME team adopted Mono?
275 A: Mono is too new to be adopted by those groups. We hope that the
276 tools that we will provide will be adopted by free software
277 programmers including the GNOME Foundation members and the GNOME
280 Q: Should GNOME programmers switch over to Mono now?
282 A: It is still far to early for discussions of "switching over." No
283 pieces of Mono will be ready within the next six months, and a
284 complete implementation is roughly one year away.
286 We encourage GNOME developers to continue using the existing tools,
287 libraries and components. Improvements made to GNOME will have an
288 impact on Mono, as they would be the "back-end" for various classes.
290 Q: Will Mono include compatibility with Bonobo components? What is the
291 relationship between Mono and Bonobo?
293 A: Yes, we will provide a set of classes for implementing and using
294 Bonobo components from within Mono. Mono should allow you to write
295 Bonobo components more easily, just like .NET on Windows allows you
296 to export .NET components to COM.
298 Q: Does Mono depend on GNOME?
300 A: No, Mono does not depend on GNOME. We use a few packages produced by
301 the GNOME team like the `glib' library.
303 Q: But will I be able to build GNOME applications?
305 A: Yes, we will enable people to write GNOME applications using Mono.
307 Q: Do you have C# bindings for GNOME?.
309 A: Yes, we currently bind libgnome, libgnomecanvas, and libgnomeui --
310 although I dare say I have no idea how functional the bindings are
311 outside of what I tested in the sample app. I imagine other libraries
312 under the GNOME framework will be added on an as-needed (and as-requested)
313 basis...although a truly good bonobo binding will have to wait on the CORBA
314 remoting support which has been started recently.
319 Q: Will Mono enable GUI applications to be authored?
321 A: Yes, you will be able to build GUI applications. Indeed, that is our
322 main focus. We will provide both the Windows.Forms API and the Gtk# API.
324 Q: What is the difference between Gtk# and System.Windows.Forms?
326 A: Gtk# is a set of bindings for the Gtk+ toolkit for C# (and other
327 CIL-enabled languages). System.Windows.Forms is an API defined
328 by Microsoft to build GUI applications.
330 Q: Why not implement System.Windows.Forms on top of Gtk# or Qt#?
334 Although it is possible to run simple Windows.Forms applications
335 with the Gtk#-based backend of Windows.Forms, it is very unlikely
336 that the implementation will ever implement everything needed for
337 full compatibility with Windows.Forms.
339 The reason is that Windows.Forms is not a complete toolkit, and to
340 work around this problem some of the underlying Win32 foundation is
341 exposed to the programmer in the form of exposing the Windows
342 message handler (WndProc). Any control can override this method.
343 Also developers often P/Invoke into Win32 to get to functionality
344 that was not wrapped.
346 To achieve full compatibility, we would have to emulate this, and
347 it would take too long.
349 For more details see the <a href="winforms.html">winforms page</a>
351 Q: Wine applications do not look like native applications, what are
352 you going to do about this?
354 A: We have already a few patches into our version of Windows.Forms
355 that makes Wine use the colors and font settings from your desktop,
356 improving the integration a lot. In the future, we will continue
357 to improve this interoperability scenario.
359 Q: Will I be able to run my smart clients on systems powered by Mono?
361 A: As long as your applications are 100% .NET and do not make use
362 of P/Invoke to call Win32 functions, your smart client applications
363 will run on Mono platforms.
365 Q: Where can I learn more about Gtk#?
367 A: The following <a href="http://gtk-sharp.sourceforge.net>link</a> sends you to the page of the project.
369 Q: What can I do with Gtk#?.
371 A: Gtk# is becoming very usable and you can create applications and
372 applets like those you see in a GNOME desktop environment. It's
373 easy to install so it's worth a try.
375 Q: How can I compile my HelloWorld.cs which uses Gtk#?.
377 A: Try: mcs --unsafe -o HelloWorld.exe -r glib-sharp -r pango-sharp -r
378 atk-sharp -r gdk-sharp -r gtk-sharp -r gdk-imaging-sharp
381 Q: Is there any way how to connect DataAdapter to some GTK# controls?
383 A: There is a sample file called `DbClient' in gtk-sharp/samples that you
384 might to look at. It is a sample program in Gtk# that adds/updates/deletes
385 information on a Postgress database. When we have the new table/tree widgets,
386 I am sure someone would write an adapter for System.Data (in Gtk2 the
387 tree/list widgets are written using a view/model, so you only need to write
388 a model that maps to the database). You can have a look at
389 gtk-sharp/sample/DbClient, where there is a GTK# application that uses
390 System.Data. It does not use DataAdapter, but DataReader though.
392 Q: Do you have an estimate for when Windows.Forms will be released?
394 A: We do not know, volunteers are working on this, but there is no set
395 date yet. The current approach is using the Wine Library to implement
398 Q: Do you have a comparission chart about the various toolkit
401 A: A document explaining this is available at: <a
402 href="http://primates.ximian.com/~miguel/toolkits.html">http://primates.ximian.com/~miguel/toolkits.html</a>.
405 ** Mono and Microsoft
407 Q: Is Microsoft helping Ximian with this project?
409 A: There is no high level communication between Ximian and Microsoft
410 at this point, but engineers who work on .NET or the ECMA groups
411 have been very friendly, and very nice to answer our questions, or
412 clarify part of the specification for us.
414 Microsoft is interested in other implementations of .NET and are
415 willing to help make the ECMA spec more accurate for this purpose.
417 Ximian was also invited to participate in the ECMA committee
418 meetings for C# and the CLI.
420 Q: Is Microsoft or Corel paying Ximian to do this?
424 Q: Do you fear that Microsoft will change the spec and render Mono
427 A: No. Microsoft proved with the CLI and the C# language that it was
428 possible to create a powerful foundation for many languages to
429 inter-operate. We will always have that.
431 Even if changes happened in the platform which were undocumented,
432 the existing platform would a value on its own.
434 Q: Are you writing Mono from the ECMA specs?
436 A: Yes, we are writing them from the ECMA specs and the published
437 materials in print about .NET.
439 Q: If my applications use Mono, will I have to pay a service fee?
441 A: No. Mono is not related to Microsoft's initiative of
442 software-as-a-service.
444 Q: Is the Mono Project is related to the Microsoft Hailstorm effort? Is
445 Ximian endorsing Hailstorm?
447 A: No. The Mono Project is focused on providing a compatible set of
448 tools for the Microsoft .NET development platform. It does not
449 address, require, or otherwise endorse the MS Passport-based
450 Hailstorm single sign-on system that is part of Windows XP and
453 Q: Will Mono or .NET applications depend on Microsoft Passport?
455 A: No. MS Passport is unrelated to running .NET compatible applications
456 produced with the Mono tools. The only thing you will need is a
457 just-in-time compiler (JIT).
459 Q: If Microsoft will release a port of their .NET platform under the
460 `Shared Source' license, why should I bother with anything else?
462 A: The Shared Source implementation will be expensive and its uses
463 will be tightly restricted, especially for commercial use. We are
464 working towards an implementation that will grant a number of
465 important rights to recipients: use for any purpose,
466 redistribution, modification, and redistribution of modifications.
468 This is what we call <a
469 href="http://www.gnu.org/philosophy/free-sw.html">Free Software</a>
471 Q: Is Mono a free implementation of Passport?
473 A: No. Mono is just a runtime, a compiler and a set of class
476 Q: Will the System.Web.Security.PassportIdentity class mean
477 that my software will depend on Passport?
479 A: No. Applications may use that API to contact a Passport site, but
480 are not required to do so.
482 As long as your application does not use Passport, you will not
485 Q: Will Mono running on Linux make Passport available for Linux?
487 A: No. However, the Passport toolkit for Linux-based web servers is
488 available from Microsoft.
490 Q: Will Mono allow me to run Microsoft Office on Linux?
492 A: No, it will not. Microsoft Office is a Windows application. To
493 learn more about running Windows applications on Intel Unix systems
494 refer to <a href="http://www.winehq.com">the Wine Project</a>.
496 Q: Can mono run the WebMatrix?
498 A: No. That requires System.Windows.Forms support which is not
499 currently implemented.
501 Q: Does mono have something like Passport?
502 Will mono have a server side Passport/Similar framework for XSP as well as client classes?
504 A: Not yet, but the client side API for authentication is not the problem.
505 We will likely have a lot of other authentication APIs, like the Liberty
506 Alliance APIs. The problem is people on the web provider end that might use
507 this for authentication.
509 <a name="platforms"></a>
512 Q: What operating systems does Mono run on?
514 A: Mono is known to run on Linux, Unix and Windows systems.
516 Q: What architectures does Mono support?
518 A: Mono today ships with a Just-in-Time compiler for x86-based
519 systems. It is tested regularly on Linux, FreeBSD and Windows
520 (with the XP/NT core).
522 There is also an interpreter, which is slower that runs on the
523 s390, SPARC and PowerPC architectures.
525 Q: Can Mono run on Windows 9x, or ME editions?
527 A: Mono requires Unicode versions of Win32 APIs to run,
528 and only a handful of *W functions is supported under Win9x.
530 There is Microsoft Layer for Unicode that provides implementation
531 of these APIs on 9x systems.
533 Unfortunately it uses linker trick for delayed load that is not
534 supported by ld, so some sort of adapter is necessary.
536 You will need MSLU and one of the following libs to link Mono to
538 href="http://mono.eurosoft.od.ua/files/unimono.zip">http://mono.eurosoft.od.ua/files/unimono.zip</a>
539 or alternatively search the net for "libunicows".
541 No changes to Mono source code required, the only thing is to make
542 sure that linker will resolve imports to adapter library instead of
543 Win32 libs. This is achieved by inserting -lunimono before
544 -lkerner32/user32 in the linker's specs file.
546 Q: Why support Windows, when you can run the real thing?
548 A: There are various reasons:
551 <li> About half the contributors to Mono are Windows developers.
552 They have many different for contributing to the effort, and
553 we find it very important to let those developers run the runtime on Windows without forcing
554 them to use a new operating system.
556 <li> Supporting Windows helps us identify the portable portions
557 of Mono from the non-portable versions of it, helping Mono
558 become more portable in the future.
560 <li> Mono does not heavily modify the windows registry, update system DLLs,
561 install DLLs to the Windows/System32 path. Another words, I knew Mono would
562 not cause any legacy enterprise applications to stop working - and it
563 hasn't. However, our CIO er is againt it because of the changes that would
564 be made to Windows 2000, such as, affecting security.
567 <a name="compatibility"></a>
570 Q: Can Mono run applications developed with the Microsoft.NET framework?
572 A: Yes, Mono can run applications developed with the Microsoft .NET Framework
573 on Unix. There are a few caveats to keep in mind: Mono has not
574 been completed yet, so a few API calls might be missing; And in
575 some cases the Mono behavior *might* be incorrect.
577 Q: Will missing API entry points be implemented?
579 A: Yes, the goal of Mono is to implement precisely the .NET Framework
580 API (as well as compile-time selectable subsets, for those
581 interested in a lighter version of Mono).
583 Q: If the behavior of an API call is different, will you fix it?
585 A: Yes, we will. But we will need your assistance for this. If you find a bug
586 in the Mono implementation, please fill a bug report in <a
587 href="http://bugzilla.ximian.com">http://bugzilla.ximian.com</a>.
588 Do not assume we know about the problem, we might not, and using the bug tracking
589 system helps us organize the development process.
591 Q: Can I develop my applications on Windows, and deploy on a supported
592 Mono platform (like Linux)?
596 As of today, Mono is not 100% finished, so it is sometimes useful
597 to compile the code with Mono, to find out if your application
598 depends on unimplemented functionality.
600 Q: Will applications run out the box with Mono?
602 A: Sometimes they will. But sometimes a .NET application might invoke
603 Win32 API calls, or assume certain patterns that are not correct
604 for cross-platform applications.
606 Q: What is a 100% .NET application?
608 A: A `100% .NET application' is one that only uses the APIs defined
609 under the System namespace and does not use P/Invoke. These
610 applications would in theory run unmodified on Windows, Linux,
611 HP-UX, Solaris, MacOS X and others.
613 Note that this requirement also holds for all assemblies used by the
614 application. If one of them is Windows-specific, then the entire program
615 is not a 100% .NET application.
617 Furthermore, a 100% .NET application must not contain non-standard data
618 streams in the assembly. For example, Visual Studio .NET will insert a
619 <tt>#-</tt> stream into assemblies built under the "Debug" target.
620 This stream contains debugging information for use by Visual Studio .NET;
621 however, this stream can not be interpreted by Mono (unless you're willing
624 Thus, it is recommended that all Visual Studio .NET-compiled code be
625 compiled under the Release target before it is executed under Mono.
627 Q: Can I execute my Visual Studio .NET program (Visual Basic .NET, Visual C#,
628 Managed Extensions for C++, etc.) under Mono?
630 A: Yes, with some reservations.
632 The .NET program must either be a 100% .NET application, or (somehow) have
633 all dependent assemblies available on all desired platforms. (How to do so
634 is outside the bounds of this FAQ.)
636 Mono must also have an implementation for the .NET assemblies used. For
637 example the System.EnterpriseServices namespace is part of .NET, but it
638 has not been implemented in Mono. Thus, any applications using this
639 namespace will not run under Mono.
641 With regards to languages, C# applications tend to be most portable.
643 Visual Basic .NET applications are portable, but Mono's
644 Microsoft.VisualBasic.dll implementation is incomplete. It is recommended
645 to either avoid using this assembly in your own code, only use the
646 portions that Mono has implemented, or to help implement the missing
647 features. Additionally, you can set 'Option Strict On', which
648 eliminates the implicit calls to the unimplemented
649 Microsoft.VisualBasic.CompilerServices.ObjectType class.
650 (Thanks to Jörg Rosenkranz.)
652 Managed Extensions for C++ is least likely to operate under Mono. Mono
653 does not support mixed mode assemblies (that is, assemblies containing both
654 managed and unmanaged code, which Managed C++ can produce). You need a
655 fully-managed assembly to run under Mono, and getting the Visual C++ .NET
656 compiler to generate such an executable can be difficult. You need to use
657 only the .NET-framework assemblies, not the C libraries (you can't use
658 <b>printf</b>(3) for example.), and you need to use
659 the linker options <tt>/nodefaultlib /entry:main mscoree.lib</tt> in
660 addition to the <tt>/clr</tt> compiler flag. You can still use certain
661 compiler intrinsic functions (such as <b>memcpy</b>(3)) and the STL.
662 You should also see <a
663 href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vcmex/html/vcgrfconvertingmanagedextensionsforcprojectsfrommixed-modetopureil.asp"
664 >Converting Managed Extensions for C++ Projects from Mixed Mode to Pure
665 Intermediate Language</a> at MSDN.
666 Finally, you can use PEVERIFY.EXE from the .NET SDK to determine if the
667 assembly is fully managed.
669 Thanks to Serge Chaban for the linker flags to use.
671 <a name="pnpproject"></a>
672 ** Mono and Portable.NET
674 Q: What are the differences between Mono and Portable.NET?
676 A: Most of Mono is being written using C#, with only
677 a few parts written in C (The JIT engine, the runtime, the
678 interfaces to the garbage collection system).
680 It is easier to describe what is unique about Mono:
682 <li> An advanced native-code compilation engine: Both
683 just-in-time compilation (JIT) and pre-compilation of CIL
684 bytecodes into native code are supported.
686 <li> A foundation for code optimization: The new code generator in
687 Mono builds on the experience of our first JIT engine, and enables
688 us to implement various advanced compiler optimization
689 tricks. With an SSA-framework, plenty of new optimizations are possible.
691 The current list of optimizations are: Peephole postpass,
692 Branch optimizations, Inline method calls, Constant folding, Constant
693 propagation, Copy propagation, Dead code elimination, Linear scan
694 global reg allocation, Conditional moves, Emit per-domain code,
695 Instruction scheduling, Intrinsic method implementations, Tail
696 recursion and tail calls, Loop related optimizations, Fast x86 FP
697 compares, Leaf procedures optimizations
699 <li> A self-hosting C# compiler written in C#, which is clean, easy
702 <li> Focus on the .NET Framework: we are tracking down the .NET
703 Framework API definition, as we believe it is the API people
704 will be most familiar with.
706 <li> A multi-platform runtime engine: both a JIT engine and an
707 interpreter exist. The JIT engine runs currently on x86
708 systems, while the interpreter works on SPARC, StrongARM,
709 s390 and PowerPC systems.
711 Our new compilation engine is being ported to the PowerPC.
713 <li> Supports Linux, BSD, Windows and Solaris at this point.
715 <li> The JIT engine is written using a portable instruction
716 selector which not only generates good code but
717 is also the foundation to re-target the JIT engine to other
720 <li> Full support for remoting in the runtime.
722 <li> The C# compiler, the JIT engine and the class libraries are
723 mature enough that the whole system has been self-hosting
724 since April 2002. This means that we develop Mono
725 completely with itself at this point.
727 By forcing ourselves to use our own code to develop our
728 tools, we bug fix problems rapidly, and the system is
729 overall more robust and tested than if we did not.
731 <li> We have a great community of developers, without which Mono
732 would not be possible.
735 In general, Mono is more mature and complete since it has been used
736 to develop itself, which is a big motivator for stability and
737 correctness, while Portable.NET remains pretty much an untested
740 Q: I hear Mono keeps changing the P/Invoke API, why?
742 A: We are just fixing our implementation to be compatible with the
743 Microsoft implementation. In other words, the Mono P/Invoke API is
744 more complete when compared to the Portable.NET version, hence
745 various pieces of software that depend on this extended
746 functionality fail to work properly with Portable.NET.
748 <a name="webservices"></a>
751 Q: How is Mono related to Web Services?
753 A: Mono is only related to Web Services in that it will implement the
754 same set of classes that have been authored in the .NET Framework
755 to simplify and streamline the process of building Web Services.
757 But most importantly, Mono is an Open Source implementation of the
760 Q: Can I author Web Services with Mono?
762 A: You will be able to write Web Services on .NET that run on Mono and
765 Q: If Mono implements the SDK classes, will I be able to write and
766 execute .NET Web Services with it?
768 A: Yes. When the project is finished, you will be able to use the
769 same technologies that are available through the .NET Framework SDK
770 on Windows to write Web Services.
772 Q: What about Soup? Can I use Soup without Mono?
774 A: Soup is a library for GNOME applications to create SOAP servers and
775 SOAP clients, and can be used without Mono. You can browse the
776 source code for soup using <a
777 href="http://cvs.gnome.org/bonsai">GNOME's Bonsai</a>.
781 A: Yes. The CLI contains enough information about a class that
782 exposing it to other RPC systems (like CORBA) is really simple, and
783 does not even require support from an object.
785 <a href="http://remoting-corba.sourceforge.net/">Remoting.CORBA</a> is
786 a CORBA implementation that is gaining momentum.
788 Building an implementation of the Bonobo interfaces once this is ready
789 should be relatively simple.
791 Q: Can I serialize my objects to other things other than XML?
793 A: Yes, although the serializing tools have not yet been planned, and
794 you would probably have to implement them yourself.
796 Q: Will Mono use ORBit?
798 A: There are a few advantages in using ORBit, like reusing existing code
799 and leveraging all the work done on it. Michael Meeks has posted
800 a few <a href="http://lists.ximian.com/archives/public/mono-list/2002-September/008592.html">reasons</a>,
801 as well as some <a href="http://lists.ximian.com/archives/public/mono-list/2002-September/008657.html">ideas</a>
802 that could be used to reuse ORBit.
804 Most users are likely to choose a native .NET solution, like <a href="http://cvs.gnome.org/bonsai">Remoting.CORBA</a>
807 <a name="monodoc"></a>
812 A: MonoDoc is a graphical documentation browser for the Mono class
813 libraries. Currently, monodoc consists of a Gtk# application and is
814 in heavy development.
817 ** Development Tools and Issues
819 Q: I am having trouble compiling a new version of Mono from CVS, it
820 complains about my runtime being out of sync.
822 A: To upgrade your class libraries and compiler, see the
823 INSTALL.txt in the MCS directory.
825 The single biggest source of confusion seems to be the "Your
826 runtime is out of sync" messages. Realize that this is *normal*
827 while BUILDING. Think about it: you're building a new class
828 library with the old runtime. If the new class library references
829 a function that the old runtime knows nothing about, the runtime
830 system issues this warning.
832 Basically what needs to happen is for a new mono runtime to be
833 compiled, then the corlib class library be compiled, and once this
834 is done, install the new runtime, followed by corlib.
836 Once this is done, you can continue building your entire
839 For instance you just need to:
840 1.- Upgrade your Mono runtime (you might better do it with the
841 mono-build.sh script available in the <a
842 href="http://www.go-mono.com">download</a> page.
843 2.- Get the latest mono-lite tarball from the daily snapshots
844 <a href="http://www.go-mono.com/daily/">page</a>, unzip and
845 untar and copy all the dll files to your install path lib
846 directory (typically pointed by the $MONO_PATH variable).
847 Copy all the exe files to the install path bin directory.
848 3.- Then checkout or update your mcs CVS copy. Then follow
849 the steps described in mcs/INSTALL.txt.
851 Q: Will it be possible to use the CLI features without using byte codes
854 A: Yes. The CLI engine will be made available as a shared library.
855 The garbage collection engine, the threading abstraction, the
856 object system, the dynamic type code system and the JIT will be
857 available for C developers to integrate with their applications if
860 Q: Will you have new development tools?
862 A: With any luck, Free Software enthusiasts will contribute tools to
863 improve the developer environment. These tools could be developed
864 initially using the Microsoft implementation of the CLI and then
865 executed later with Mono.
867 We are recommending people to use and contribute to existing
868 projects like SharpDevelop, Anjuta and Eclipse.
870 Q: What kind of rules make the Common Intermediate Language useful for
873 A: The main rule is that the stack in the CLI is not a general purpose
874 stack. You are not allowed to use it for other purposes than
875 computing values and passing arguments to functions or return
878 At any given call or return instruction, the types on the stack
879 have to be the same independently of the flow of execution of your
882 Q: Is it true that the CIL is ideal for JITing and not efficient for
885 A: The CIL is better suited to be JITed than JVM byte codes, but you
886 can interpret them as trivially as you can interpret JVM byte
889 Q: Isn't it a little bit confusing to have the name of "XSP" (the same
890 as in the Apache Project) for the ASP.NET support in Mono?.
892 A: In Mono, xsp is just the name of the C# code generator for ASP.NET
893 pages. In the Apache Project, it is a term for the "eXtensible Server
894 Pages" technology so as they are very different things, they don't
897 Q: Is there any plan to develop an aspx server for Mono?.
899 A: The XSP reference server is available and you can also use mod_mono
902 Q: Is there any way I can develop the class libraries using Linux yet?
904 A: Yes. Mono has been self hosting since May 2002.
906 Q: Is there any way I can install a known working copy of mono in /usr,
907 and an experimental copy somewhere else, and have both copies use
908 their own libraries? (I'm still not very good at library paths in
911 A: Yes. Just use two installation prefixes.
913 Q: How should I write tests or a tests suite?
915 A: If you do a test suite for C#, you might want to keep it
916 independent of the Mono C# compiler, so that other compiler
917 implementations can later use it.
919 Q: Would it be too terrible to have another corlib signed as mscorlib?
921 A: We rename corlib to mscorlib also when saving the PE files, in fact,
922 the runtime can execute program created by mono just fine.
924 Q: Is it possible to build a C# file to some sort of intermediate format which
925 can linked into a final module, like the traditional .c -> .o -> .so path?
929 mcs /target:library file1.cs, mcs /target:library file2.cs,
930 mcs /target:exe file1.dll file2.dll /out:mybin.exe
932 Q: Is there any plans for implementing remoting in the near future?
934 A: The remoting infrastructure is in place. We have implementations
935 of the TcpChannel, HttpChannel and the Soap and Binary Formatters.
936 They are compatible with .NET.
938 However, some classes from the library may have a different binary
939 representation, because they may have a different internal data
940 structure, so for example you won't be able to exchange a Hastable
941 object between Mono and MS.NET. It should not be a problem if you
942 are using primitive types, arrays or your own classes. In any case,
943 could you post a test case?
946 Q: My C code uses the __stdcall which is not availble on Linux, how can I
947 make the code portable Windows/Unix across platforms?
949 A: Replace the __stdcall attribute with the STDCALL macro, and include this
950 in your C code for newer gcc versions:
953 #define STDCALL __attribute__((stdcall))
956 Q: I want to be able to execute Mono binaries, without having to use the "mono"
957 command. How can I do this?
959 A: From Carlos Perelló:
961 <i>I think that the best solution is the binfmt feature with the
962 wrapper that exists with Debian packages at:
964 <a href="http://www.debianplanet.org/mono/dists/unstable/main/source/admin/">http://www.debianplanet.org/mono/dists/unstable/main/source/admin/</a>
966 If you want use it with Big endian machines, you should apply a patch
967 (<a href="http://carlos.pemas.net/debian/mono/binfmt-detector-cli.c.diff">http://carlos.pemas.net/debian/mono/binfmt-detector-cli.c.diff</a>)
969 It works really good and lets you use wine also, it reads the .exe file
970 headers and check if it's a .net executable.
972 This way you just execute: ./my-cool-mono-application.exe and it works
973 without the need of any wrapper.</i>
975 Q: I see funny characters when I run programs, what is the problem?
977 A: (From Peter Williams and Gonzalo Paniagua):
979 This is Red Hat 9 (probably) using UTF8 on its console; the bytes are
980 the UTF8 endianness markers. You can do:
982 LC_ALL=C mono myexe.exe
984 And they wont show up.
986 Alternatively, you can do:
990 to enable UTF-8 on the console.
995 Q: Does Mono support ASP.NET?
999 Mono supports ASP.NET, we have shown an unmodified IBuySpy
1000 installation running on Mono as well as various other programs. You can
1001 try it yourself downloading the XSP server.
1003 Q: Do I need install cygwin to work on ASP.NET in mono or Linux is enough since
1004 it is self host right now.
1008 Q: How can I run ASP.NET-based applications with Mono?
1010 A: You need the Mono runtime and a hosting web server. Currently we distribute a
1011 small web server called `xsp' which is used to debug applications, or you can choose
1012 to use Daniel's Apache 2 module.
1014 Q: Any plan to make ASP.NET in mono works with Apache in Linux?.
1016 A: Daniel has authored an Apache2 Module for Mono that hosts the ASP.NET runtime
1017 and is available here: <a
1018 href="http://apacheworld.org/modmono/">http://apacheworld.org/modmono/</a>
1020 Q: Will you support Apache 1?
1022 A: Modules developed for Apache 2 are not compatible with Apache 1.3
1023 Daniel plans to support Apache 1.3 in the future but the current focus is on
1024 Apache 2, because of the better support for threading and Windows.
1026 Q: Can I run Apache 1 and Apache 2 on the same machine?
1028 You can always keep a copy of Apache 2 running in parallel with your Apache
1029 1.3 (either different port or using a reverse proxy).
1031 You can also bind the two servers to different IP addresses on the
1032 same physical machine.
1037 Q: What is the status of ADO.NET support?. Could I start migrating
1038 applications from MS.NET to Mono?.
1040 A: You could start right now using the ADO.NET support in mono, of course,
1041 if you want to help filling the missing gaps while you develop your app
1042 :-) Well, what I mean is that we're not that far to having full ADO.NET
1043 support in Mono, and we've got a lot of working things, so if we could
1044 get more help, we'd finish it really soon :-)
1046 Q: In developing the data architecture for the application are there and
1047 objects I should stay away from in order to insure the smoothest possible
1048 transition (minimum code rewrite) to Mono's ADO.NET implementation? (For
1049 example, strongly typed datasets versus untyped datasets, etc...)
1051 A: We are implementing all the classes in Microsoft .NET's System.Data, so
1052 you can be sure that things will work the same in Mono as with the Microsoft
1055 Q: Does Mono can to connect to Sybase by using Mono.Data.*?
1057 A: Yes. use Mono.Data.SybaseClient. First of all you have to create a
1058 SybaseConnection, and then, from it, use it as any other
1059 IDbConnection-based class.
1064 Q: Why don't you use Java? After all, there are many languages that
1067 A: You can get very good tools for doing Java development on free
1068 systems right now. <a href="http://www.redhat.com">Red Hat</a> has
1069 contributed a <a href="http://gcc.gnu.org">GCC</a> <a
1070 href="http://gcc.gnu.org/java">front-end for Java</a> that can take
1071 Java sources or Java byte codes and generate native executables; <a
1072 href="http://www.transvirtual.com">Transvirtual</a> has implemented
1073 <a href="http://www.kaffe.org">Kaffe</a> a JIT engine for Java;
1074 Intel also has a Java VM called <a
1075 href="http://www.intel.com/research/mrl/orp">ORP</a>.
1077 The JVM is not designed to be a general purpose virtual machine.
1078 The Common Intermediate Language (CIL), on the other hand, is
1079 designed to be a target for a
1080 wide variety of programming languages, and has a set of rules
1081 designed to be optimal for JITers.
1083 Q: Could Java target the CLI?
1085 A: Yes, Java could target the CLI, Microsoft's J# compiler does that.
1087 The <a href="http://weblog.ikvm.net/">IKVM</a> project builds a
1088 Java runtime that works on top of .NET and on top of Mono. IKVM is
1089 essentially a JIT compiler that translates from JVM bytecodes into
1090 CIL instructions, and then lets the native JIT engine take over.
1092 Q: Is it possible to write a JVM byte code to CIL converter?
1094 A: Yes, it is possible. Here are a few starting point:
1097 * A byte code representation is really a flattened forest of
1098 trees. Look at the Mono JIT engine to see how we compute
1099 the basic blocks (this is used to figure out the "trees").
1101 The forest is just an array of trees.
1103 Indeed, run the JIT engine with -d (mono -d prog.exe) and
1104 you will see how these trees look like.
1106 You will have to do something similar for Java.
1108 * Each "forest of trees" has a meaning. This meaning can now
1109 be translated into the equivalent "meaning" in CLR-land.
1112 See also the <a href="http://weblog.ikvm.net/">IKVM project</a>
1114 Q: Could mono become a hybrid CIL/java platform?
1116 A: No. It is quite far from the philosophy of the project. The idea of Mono
1117 is, to have only _one_ VM, on which all can run. And if there existing a
1118 binary-converter from Java-.class to IL and if there existing something
1119 like J-Sharp on Mono, you can write programs in Java, which than can run
1120 on Mono. You do not need two bindings (like your example: GTK-Sharp _and_
1121 Java-Gnome). You need only _one_ of it (GTK-Sharp). Thats the idea of Mono.
1122 An other point is, that there are no people, who use Open Source-JVMs. They
1123 all prefer Suns original. But for Unix there don't exist a .NET-Framework.
1124 So it is possible, that in the future Mono is the standard .NET for Unixes.
1126 Q: Do you plan to implement a Javascript compiler?
1128 A: Yes. The beginnings of the JScript compiler can be found on CVS.
1129 Cesar coordinates this effort.
1131 Q: Can Mono or .NET share system classes (loaded from mscore.dll and other
1132 libs) or will it behave like Sun's Java VM?
1134 A: What you can do with mono is to load different applications in their own
1135 application domain: this is a feature of the CLR that allows sandboxing
1136 applications inside a single process space. This is usualy exploited to
1137 compartmentalize different parts of the same app, but it can also be
1138 effectively used to reduce the startup and memory overhead.
1139 Using different appdomains the runtime representation of types and
1140 methods is shared across applications.
1142 <a name="extending"></a>
1145 Q: Would you allow other classes other than those in the
1148 A: Yes. The Microsoft class collection is very big, but it is by no
1149 means complete. It would be nice to have a port of `Camel' (the
1150 Mail API used by Evolution inspired by Java Mail) for Mono
1153 You might also want to look into implementing CORBA for Mono. Not
1154 only because it would be useful, but because it sounds like a fun
1155 thing to do, given the fact that the CLI is such a type rich
1158 For more information on extending Mono, see our <a
1159 href="ideas.html">ideas</a> page.
1161 Q: Do you plan to Embrace and Extend .NET?
1163 A: Embracing a good technology is good. Extending technologies in
1164 incompatible ways is bad for the users, so we do not plan on
1165 extending the technologies.
1167 If you have innovative ideas, and want to create new classes, we
1168 encourage you to make those classes operate correctly well in both
1171 Today Mono ships with a number of extra libraries that were
1172 developed either by members of the Mono community, or other
1175 Q: Is there any way I can develop the class libraries using Linux yet?
1177 A: Yes. Mono has been selfhosting since March 2002.
1179 Q: Is there any way I can install a known working copy of mono in /usr,
1180 and an experimental copy somewhere else, and have both copies use
1181 their own libraries? (I'm still not very good at library paths in
1184 A: Yes. Just use two installation prefixes.
1187 <a name="portability"></a>
1190 Q: Will Mono only work on Linux?
1192 A: Currently, we are doing our work on Linux-based systems and
1193 Windows. We do not expect many Linux-isms in the code, so it
1194 should be easy to port Mono to other UNIX variants.
1196 Q: What about Mono on non Linux-based systems?
1198 A: Our main intention at Ximian is to be able to develop GNOME
1199 applications with Mono, but if you are interested in providing a
1200 port of the Winforms classes to other platforms (frame buffer or
1201 MacOS X for example), we would gladly integrate them, as long
1202 they are under an open source license.
1204 Q: What operating systems/CPUs do you support
1206 A: Mono currently runs on Linux, Windows, Solaris and FreeBSD.
1207 There is a JIT engine available for x86 processors that can
1208 generate code and optimizations tailored for a particular CPU.
1210 Interpreters exist for the SPARC, PowerPC and StrongARM CPUs.
1212 Q: Does Mono run on Windows?
1214 A: Yes. You can get pre-compiled
1215 binaries from <a href="http://www.go-mono.com/download.html">http://www.go-mono.com/download.html</a>
1217 Q: Does Mono run on Linux?
1219 A: Yes. You can get pre-compiled
1220 binaries from <a href="http://www.go-mono.com/download.html">http://www.go-mono.com/download.html</a>
1222 Q: Will I require Cygwin to run mono?
1224 A: No. Cygwin is only required to build Mono.
1226 Q: Will Mono depend on GNOME?
1228 A: It will depend only if you are using a particular assembly (for
1229 example, for doing GUI applications). If you are just interested
1230 in Mono for implementing a `Hello World Enterprise P2P Web
1231 Service', you will not need any GNOME components.
1233 Q: Is anyone working on porting Mono to IA-64?
1235 A: Nobody is working on such port.
1237 Q: If I were about to start a Mono port to IA-64,would the same lburg code
1238 generator work for IA-64 also? or anything else need to be used for code
1239 generation(as the processor architecture is totally different from IA32)
1241 A: The lburg approach can be use for any processor architecture. But you might
1242 think in another better approach.
1244 Q: Do you plan to port Rhino to C#?.
1246 A: Eto Demerzal has started a Rhino port to C#.
1248 Q: Has anyone succeeded in building a Mac version of the C# environment.
1249 If so can you explain how?
1251 A: You could try to check with the Darwin people, or the Fink people.
1252 Mono/C# is self hosting on Linux/PPC which is the hard part, so it
1253 should be relatively simple to get it to work on MacOS
1255 <a name="reuse"></a>
1256 ** Reusing Existing Code
1258 Q: What projects will you reuse or build upon?
1260 A: We want to get Mono in the hands of programmers soon. We are
1261 interested in reusing existing open source software.
1263 Q: What about Intel's research JIT framework, ORP?
1265 A: At this time, we are investigating whether we can use elements of
1266 ORP for Mono. ORP is a research JIT engine that has a clearly
1267 defined API that splits the JIT from the GC system and the actual
1268 byte code implementation.
1270 We are using some pieces of ORP (Their code generation interface)
1271 and we use it as a source of inspiration for optimizations. Paolo
1272 and Dietmar consider ORP as being one of the best JIT engines out
1273 there (and their research work and papers are very useful if you are
1274 interested in JIT technology).
1276 Q: What about using GNU Lightning?
1278 A: We are not using GNU Lightning. Our JIT is using an instruction
1279 selector based on tree-pattern matching, and a code generation
1280 interface that is very tied to the current architecture.
1282 Q: Will I be able to use Microsoft SQL Server 2000 or will I need to switch
1283 to a specific Open Source Database. Will I need to recode?
1285 A: There should not be any need to recode.
1287 Q: What do I need to watch out for when programming in VB.NET so that I'm
1288 sure to be able to run those apps on Linux?
1290 A: Not making any P/Invoke or DLL calls should and not using anything in
1291 the Microsoft.* namespaces should suffice. Also do not use any
1292 Methods/Classes marked as "This type/method supports the .NET Framework
1293 infrastructure and is not intended to be used directly from your code."
1294 even if you know what these classes/methods do.
1296 Q: Will built-in reporting be supported for crystal reports? This is a
1297 heavily used part of our system.
1299 A: Probably not. Crystal Reports are propriety. Someone may try to emulate
1300 the behavior, but no-one has yet volunteered.
1302 Q: Who about writing to the registry? As I understand it, Linux does not have
1303 a counterpart to the registry. Should I avoid relying on that feature?
1305 A: Try to avoid it. Although there would be a emulation for registry in
1306 Mono too. GNOME does have a registry like mechanism for configuration. But
1307 Even if gnome has a configuration system similar to the registry, the keys
1308 will not be equal, so you will probably end up having to do some runtime
1309 detection, and depending on this load an assembly that has your
1310 platform-specific hacks.
1312 Q: System.Data.SqlClient with FreeTDS, will you port parts of these to C# and
1315 A: if their license is compatible with mono's, yes, we'd think about porting
1316 them. If not, we'll continue with the plan of using FreeTDS.
1321 Q: Are you working on a GCC front-end to C#? A GCC back-end that will
1322 generate CIL images? What about making a front-end to GCC that
1323 takes CIL images and generates native code?
1325 A: We are currently seeking volunteers for those projects.
1326 Visit the <a href="contributing.html">contributing</a> section if
1329 Q: But would this work around the GPL in the GCC compiler and allow
1330 people to work on non-free front-ends?
1332 A: People can already do this by targeting the JVM byte codes (there
1333 are about 130 compilers for various languages that target the JVM).
1335 Q: Why are you writing a JIT engine instead of a front-end to GCC?
1337 A: We want the JIT engine and runtime engine because they will be able
1338 to execute CIL executables generated on Windows, and so no recompilation
1341 <a name="performance"></a>
1344 Q: How fast will Mono be?
1346 A: We can not predict the future, but a conservative estimate is that
1347 it would be at least `as fast as other JIT engines'.
1349 We would like to ship various JIT engines with Mono, just like
1350 Microsoft has done with their .NET development platform. We could
1351 provide a faster, JIT for fast load times but lower performance,
1352 and an and an optimizing JIT that would be slower at generating
1353 code but produce more optimal output.
1355 The CIL has some advantages over the Java byte code: it is really
1356 an intermediate representation and there are a number of
1357 restrictions on how you can emit CIL code that simplify creating
1360 For example, on the CIL, the stack is not really an abstraction
1361 available for the code generator to use at will. Rather, it is a
1362 way of creating a postfix representation of the parsed tree. At
1363 any given call point or return point, the contents of the stack are
1364 expected to contain the same object types independently of how the
1365 instruction was reached.
1367 <a name="licensing"></a>
1370 Q: Will I be able to write proprietary applications that run with
1373 A: Yes. The licensing scheme is planned to allow proprietary
1374 developers to write applications with Mono.
1376 Q: What license or licenses are you using for the Mono Project?
1378 A: The C# Compiler is released under the terms of the <a
1379 href="http://www.opensource.org/licenses/gpl-license.html">GNU GPL</a>. The runtime
1380 libraries are under the <a
1381 href="http://www.opensource.org/licenses/lgpl-license.html">GNU
1382 Library GPL</a>. And the class libraries are released
1383 under the terms of the <a
1384 href="http://www.opensource.org/licenses/mit-license.html">MIT X11</a>
1387 The Mono runtime and the Mono C# Compiler are also available under
1388 a proprietary license for those who can not use the LGPL and the
1391 For licensing details, contact <a
1392 href="mailto:mono-licensing@ximian.com">mono-licensing@ximian.com</a>
1395 Q: I would like to contribute code to Mono under a particular
1396 license. What licenses will you accept?
1398 A: We will have to evaluate the licenses for compatibility first,
1399 but as a general rule, we will accept the code under the same
1400 terms of the "container" module.
1402 <a name="patents"></a>
1405 Q: Could patents be used to completely disable Mono (either submarine
1406 patents filed now, or changes made by Microsoft specifically to
1407 create patent problems)?
1409 A: First some background information.
1411 The .NET Framework is divided in two parts: the ECMA/ISO covered
1412 technologies and the other technologies developed on top of it like
1413 ADO.NET, ASP.NET and Windows.Forms.
1415 Mono implements the ECMA/ISO covered parts, as well as being a
1416 project that aims to implement the higher level blocks like
1417 ASP.NET, ADO.NET and Windows.Forms.
1419 The Mono project has gone beyond both of those components and has
1420 developed and integrated third party class libraries, the most
1421 important being: Debugging APIs, integration with the Gnome
1422 platform (Accessibility, Pango rendering, Gdk/Gtk, Glade, GnomeUI),
1423 Mozilla, OpenGL, extensive database support (Microsoft only
1424 supports a couple of providers out of the box, while Mono has
1425 support for 11 different providers), our POSIX integration
1426 libraries and finally the embedded API (used to add scripting to
1427 applications and host the CLI, or for example as an embedded
1430 The core of the .NET Framework, and what has been patented by
1431 Microsoft falls under the ECMA/ISO submission. Jim Miller at
1432 Microsoft has made a statement on the patents covering ISO/ECMA,
1433 (he is one of the inventors listed in the patent): <a
1434 href="https://mailserver.di.unipi.it/pipermail/dotnet-sscli/msg00218.html">here</a>.
1436 Basically a grant is given to anyone who want to implement those
1437 components for free and for any purpose.
1439 The controversial elements are the ASP.NET, ADO.NET and
1440 Windows.Forms subsets. Those are convenient for people who need
1441 full compatibility with the Windows platform, but are not required
1442 for the open source Mono platform, nor integration with today's
1443 Mono's rich support of Linux.
1445 The Mono strategy for dealing with these technologies is as
1446 follows: (1) work around the patent by using a different
1447 implementation technique that retains the API, but changes the
1448 mechanism; if that is not possible, we would (2) remove the pieces
1449 of code that were covered by those patents, and also (3) find prior
1450 art that would render the patent useless.
1452 Not providing a patented capability would weaken the
1453 interoperability, but it would still provide the free software /
1454 open source software community with good development tools, which
1455 is the primary reason for developing Mono.
1457 The patents do not apply in countries where software patents are
1460 For Linux server and desktop development, we only need the ECMA
1461 components, and things that we have developed (like Gtk#) or Apache
1464 Q: Is Mono only an implementation of the .NET Framework?
1466 A: Mono implements both the .NET Framework, as well as plenty of class
1467 libraries that are either Unix specific, <a
1468 href="http://www.gnome.org">Gnome</a> specific, or that are not
1469 part of the .NET Framework but people find useful.
1471 The following map shows the relationship between the components:
1473 <img src="http://primates.ximian.com/~miguel/tmp/map.png">
1476 ** Miscellaneous Questions
1478 Q: You say that the CLI allows multiple languages to execute on the
1479 same environment. Isn't this the purpose of CORBA?
1481 A: The key difference between CORBA (and COM) and the CLI is that the
1482 CLI allows "data-level interoperability" because every
1483 language/component uses the same data layout and memory management.
1485 This means you can operate directly upon the data types that someone
1486 else provides, without having to go via their interfaces. It also
1487 means you don't have to "marshal" (convert) parameters (data
1488 layouts are the same, so you can just pass components directly) and
1489 you don't have to worry about memory management, because all
1490 languages/components share the same garbage collector and address
1491 space. This means much less copying and no need for reference
1494 Q: Will you support COM?
1496 A: The runtime will support XPCOM on Unix systems and COM on Windows.
1497 Most of the code for dynamic trampolines exists already.
1499 Q: Will Ximian offer certifications on Mono or related technologies?.
1501 A: It's possible. But there is no plan about this. So the short answer is no.
1503 Q: Are there any Boehm's GC binaries?
1505 A: Yes. You can find RPMs <a href="http://java.thn.htu.se/~toor/">here</a>, though
1506 if your distribution provides the correct packages, you should use those.
1507 The suggested version of the Boehm GC is 6.1.
1509 Q: How can I report a bug?
1511 A: The best thing is to track down the bug and provide a simple test to
1512 reproduce the bug. You can then add the bug to the
1513 <a href="http://bugzilla.ximian.com/enter_bug.cgi">bugtracking system</a>.
1515 Please provide information about what version of mono you're using
1516 and any relevant details to be able to reproduce the bug. Note that
1517 bugs reported on the mailing-list may be easily forgotten, so it's
1518 better to file them in the <a href="http://bugzilla.ximian.com/enter_bug.cgi">bug tracking system</a>.
1520 Q: Does mcs support the same command line options as the MS C#
1523 A: The Mono C# compiler now supports the same command line
1524 arguments as the Microsoft C# compiler does.
1526 Q: How about getting searchable archives on lists.ximian.com?
1528 A: You can perform a search on the mono-related mailing lists
1529 <a href="http://www.go-mono.com/mailing-lists.html">here</a>.
1531 Q: When using mono from cvs or from a snapshot, I get an error messaage
1532 saying that Mono and the runtime are out of sync. How do I fix that?
1534 A: If you use mono from cvs, you need to be prepared for changes in the
1535 runtime internals. This means that you should keep a working setup
1536 before blindling updating (a working setup may just be the last released
1537 tarball or a recent binary snapshot).
1538 Usually, compiling corlib with mcs before recompiling the C runtime does
1539 the right thing (but occasionally you may need to do it the other
1542 Q: Why are you going for a GtkHtml implementation?
1544 A: GtkHTML is just a lightweight HTML rendering engine that does not
1545 support CSS, so we need it to look decent for those of us that will
1546 be using the documentation in our day-to-day work on Linux. The
1547 Web-based interfaces lack the agility that you get from a native GUI
1548 tool to browse your documentation. Probably later on, we will write
1549 scripts and generate a full documentation set that is web-browsable,
1550 but we need a command-line and GUI tools that we can use natively on
1551 Linux when disconnected from the Web (and that has better
1552 interactions than a web page).
1554 Q: Is there a command-line tool that allows me to access .NET interactively?
1556 A: There are several but one that is free software and uses MCS is the one
1557 Dennis Lu from Rice University is working on; a REPL C# interpreter.
1559 Q: Is it possible to use Visual C++ with Mono?.
1561 A: It's possible to run VC++ generated apps under Mono, but we do not
1562 provide a Manager C++ compiler ourselves.
1564 Q: Does Mono support generics?.
1566 A: Mono doesn't support generics currently but a lot of work is being
1569 <a name="problems"></a>
1570 ** Mono Common Problems
1572 If you are having problems compiling or running Mono software
1573 or if you think that you found a bug, etc. Please visit the
1574 <a href="http://monoevo.sf.net/mono-common-problems.html">Mono Common Problems</a> document and try there.
1578 The FAQ contains material contributed by Miguel de Icaza, Jaime Anguiano, Lluis Sánchez.