Mono is a

free and open-source Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source ...

.NET Framework The .NET Framework (pronounced as "''dot net"'') is a proprietary software framework developed by Microsoft that runs primarily on Microsoft Windows. It was the predominant implementation of the Common Language Infrastructure (CLI) until bein ...

-compatible

software framework In computer programming, a software framework is an abstraction in which software, providing generic functionality, can be selectively changed by additional user-written code, thus providing application-specific software. It provides a standard ...

. Originally by Ximian, it was later acquired by

Novell Novell, Inc. was an American software and services company headquartered in Provo, Utah, that existed from 1980 until 2014. Its most significant product was the multi- platform network operating system known as Novell NetWare. Under the le ...

, and is now being led by

Xamarin Xamarin is a Microsoft-owned San Francisco-based software company founded in May 2011 by the engineers that created Mono, Xamarin.Android (formerly Mono for Android) and Xamarin.iOS (formerly MonoTouch), which are cross-platform implementat ...

, a subsidiary of

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...

and the

.NET Foundation The .NET Foundation is an organization incorporated on March 31, 2014, by Microsoft to improve open-source software development and collaboration around the .NET Framework. It was launched at the annual Build 2014 conference held by Microsoft. T ...

. Mono can be run on many

software system A software system is a system of intercommunicating components based on software forming part of a computer system (a combination of hardware and software). It "consists of a number of separate programs, configuration files, which are used to se ...

History

When Microsoft first announced their

in June 2000 it was described as "a new platform based on Internet standards", and in December of that year the underlying

Common Language Infrastructure The Common Language Infrastructure (CLI) is an open specification and technical standard originally developed by Microsoft and standardized by ISO/IEC (ISO/IEC 23271) and Ecma International (ECMA 335) that describes executable code and a ...

was published as an open standard, "ECMA-335", opening up the potential for independent implementations. Miguel de Icaza of Ximian believed that .NET had the potential to increase programmer productivity and began investigating whether a Linux version was feasible. Recognizing that their small team could not expect to build and support a full product, they launched the Mono open-source project, on July 19, 2001 at the O'Reilly conference. After three years of development, Mono 1.0 was released on June 30, 2004. Mono evolved from its initial focus of a developer platform for Linux desktop applications to supporting a wide range of architectures and operating systems - including embedded systems.

acquired Ximian in 2003. After Novell was acquired by

Attachmate Attachmate Corporation is a 1982-founded software company which focused on secure terminal emulation, legacy integration, and managed file transfer software. Citrix-compatibility and Attachment ''Reflection'' were enhanced/added offerings. His ...

in April 2011, Attachmate announced hundreds of layoffs for the Novell workforce, putting in question the future of Mono. On May 16, Miguel de Icaza announced in his blog that Mono would continue to be supported by

, a company he founded after being laid off from Novell. The original Mono team had also moved to the new company. Xamarin planned to keep working on Mono and had planned to rewrite the proprietary .NET stacks for iOS and Android from scratch, because Novell still owned MonoTouch and Mono for Android at the time. After this announcement, the future of the project was questioned, MonoTouch and Mono for Android being in direct competition with the existing commercial offerings now owned by

, and considering that the Xamarin team would have difficulties proving that they did not use technologies they formerly developed when they were employed by

for the same work. However, in July 2011, Novell, now a subsidiary of Attachmate, and Xamarin, announced that it granted a perpetual license to Xamarin for Mono, MonoTouch and Mono for Android, which officially took stewardship of the project.

Current status and roadmap

Mono's current version is 6.0.0 (). This version provides the core API of the

and support for Visual Basic.NET and C# 7.0. LINQ to Objects, XML, and SQL are part of the distribution.

Windows Forms Windows Forms (WinForms) is a free and open-source graphical (GUI) class library included as a part of Microsoft .NET, .NET Framework or Mono Framework, providing a platform to write client applications for desktop, laptop, and tablet PCs. Whi ...

2.0 is also supported, but not actively developed, and as such its support on Mono is incomplete. Version 4.0 was the first version that incorporates Microsoft original source code that was released by Microsoft as part of the

.NET Core The domain name net is a generic top-level domain (gTLD) used in the Domain Name System of the Internet. The name is derived from the word ''network'', indicating it was originally intended for organizations involved in networking technologies ...

project. As of January 14, 2021, Mono has full support for all the features in .NET 4.7 except Windows Presentation Foundation (WPF) (which the Mono team do not plan to support due to the amount of work it would need) and Windows Workflow Foundation (WF), and with only limited support for

Windows Communication Foundation The Windows Communication Foundation (WCF), previously known as Indigo, is a free and open-source runtime and a set of APIs in the .NET Framework for building connected, service-oriented applications. .NET Core 1.0, released 2016, did not supp ...

(WCF) and the ASP.NET async stack. However, System.Web and WCF are candidates for 'almost immediate' porting from the .NET reference source back to Mono. Some missing parts of the

are under development in an experimental Mono subproject calle
''Olive''
The Mono project has also created a Visual Basic .NET compiler and a runtime designed for running VB.NET applications. It is currently being developed by Rolf Bjarne Kvinge.

Moonlight

An open-source implementation of

Microsoft Silverlight Microsoft Silverlight is a discontinued application framework designed for writing and running rich web applications, similar to Adobe's runtime, Adobe Flash. A plugin for Silverlight is still available for a very small number of browsers. ...

, called

Moonlight Moonlight consists of mostly sunlight (with little earthlight) reflected from the parts of the Moon's surface where the Sun's light strikes. Illumination The intensity of moonlight varies greatly depending on the lunar phase, but even the ful ...

, has been included since Mono 1.9. Moonlight 1.0, which supports the Silverlight 1.0 APIs, was released January 20, 2009. Moonlight 2.0 supports Silverlight 2.0 and some features of Silverlight 3.0. A preview release of Moonlight 3.0 was announced in February 2010 and contains updates to Silverlight 3 support. The Moonlight project was abandoned on May 29, 2012. According to Miguel, two factors sealed the fate of the project: Microsoft added "artificial restrictions" that "made it useless for desktop programming", and the technology had not gained enough traction on the Web. In addition, Silverlight itself was deprecated by Microsoft by 2012.

Mono components

Mono consists of three groups of components: # Core components # Mono/Linux/GNOME development stack # Microsoft compatibility stack The ''core components'' include the C# compiler, the virtual machine for the

and the core class libraries. These components are based on the Ecma-334 and Ecma-335 standards, allowing Mono to provide a standards compliant, free and open-source CLI

virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...

. Microsoft issued a statement that covers both standards under their Community Promise license. The ''Mono/Linux/GNOME development stack'' provide tools for application development while using the existing

GNOME A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its characte ...

and

libraries. These include: Gtk# for

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, ins ...

(GUI) development, Mozilla libraries for working with the Gecko rendering engine, Unix integration libraries (Mono.Posix), database connectivity libraries, a security stack, and the XML schema language

RelaxNG In computing, RELAX NG (REgular LAnguage for XML Next Generation) is a schema language for XML—a RELAX NG schema specifies a pattern for the structure and content of an XML document. A RELAX NG schema is itself an XML document but RELAX NG als ...

. Gtk# allows Mono applications to integrate into the Gnome desktop as native applications. The database libraries provide connectivity to the object-relational database

db4o db4o (database for objects) was an embeddable open-source object database for Java and .NET developers. It was developed, commercially licensed and supported by Actian. In October 2014, Actian declined to continue to actively pursue and promote ...

, Firebird,

Microsoft SQL Server Microsoft SQL Server is a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications—which ...

(MSSQL),

MySQL MySQL () is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A relational database ...

Open Database Connectivity In computing, Open Database Connectivity (ODBC) is a standard application programming interface (API) for accessing database management systems (DBMS). The designers of ODBC aimed to make it independent of database systems and operating systems. An ...

(ODBC),

Oracle An oracle is a person or agency considered to provide wise and insightful counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. As such, it is a form of divination. Description The word ...

PostgreSQL PostgreSQL (, ), also known as Postgres, is a free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. It was originally named POSTGRES, referring to its origins as a successor to the ...

SQLite SQLite (, ) is a database engine written in the C programming language. It is not a standalone app; rather, it is a library that software developers embed in their apps. As such, it belongs to the family of embedded databases. It is the mo ...

, and many others. The Mono project tracks developing database components at its website. The ''Microsoft compatibility stack'' provides a pathway for porting Windows .NET applications to

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...

. This group of components include ADO.NET, ASP.NET, and

, among others. As these components are not covered by Ecma standards, some of them remain subject to patent fears and concerns.

Framework architecture

The major components of Mono include: * Code Execution Engine * Class Libraries **

Base Class Library The Standard Libraries is a set of libraries included in the Common Language Infrastructure (CLI) in order to encapsulate many common functions, such as file reading and writing, XML document manipulation, exception handling, application globa ...

** .NET Compatibility Class Libraries ** Mono specific class libraries: *** Cross platform class libraries for both Mono and .NET (Gtk#, MonoCecil, Mono.CSharp, Text.Templating) *** Unix-specific class libraries (POSIX, Filesystem in Userspace (FUSE), curses) *** Platform-specific class libraries (bindings for: Mac, iOS, Android, MeeGo) * CLI Assemblies * CLI Metadata * Mono's

Common Language Runtime The Common Language Runtime (CLR), the virtual machine component of Microsoft .NET Framework, manages the execution of .NET programs. Just-in-time compilation converts the managed code (compiled intermediate language code) into machine instru ...

** Compatible with the ECMA

/.NET

** Mono-specific enhancements: *** Mono.SIMD support *** Mono co-routines and continuations. * Mono-specific enhancements * Native interop services and COM interop * Security
Transparent Code Framework

Code Execution Engine

The Mono runtime contains a code execution engine that translates ECMA CIL byte codes into native code and supports a number of processors: ARM, MIPS (in 32-bit mode only),

SPARC SPARC (Scalable Processor Architecture) is a reduced instruction set computer (RISC) instruction set architecture originally developed by Sun Microsystems. Its design was strongly influenced by the experimental Berkeley RISC system develope ...

PowerPC PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple– IBM– ...

, S390 (in 64-bit mode), x86,

x86-64 x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging ...

and

IA-64 IA-64 (Intel Itanium architecture) is the instruction set architecture (ISA) of the Itanium family of 64-bit Intel microprocessors. The basic ISA specification originated at Hewlett-Packard (HP), and was subsequently implemented by Intel in col ...

for 64-bit modes. The code generator is exposed in three modes: * Just-in-time (JIT) compilation: The runtime will turn ECMA CIL byte codes into native code as the code runs. * Ahead-of-Time (AOT) compilation: this code turns the ECMA CIL byte codes (typically found on a .exe or .dll file) and generates native code stored in an operating system, architecture and CPU specific file (for a foo.exe file, it would produce foo.exe.so on Linux). This mode of operation compiles most of the code that is typically done at runtime. There are some exceptions like trampolines and other administrative code that still require the JIT to function, so AOT images are not fully standalone. * Full Static Compilation: this mode is only supported on a handful of platforms and takes the Ahead-of-Time compilation process one step further and generates all the trampolines, wrappers and proxies that are required into a static file that can be statically linked into a program and completely eliminates the need for a JIT at runtime. This is used on Apple's iOS, Sony's

PlayStation 3 The PlayStation 3 (PS3) is a home video game console developed by Sony Interactive Entertainment, Sony Computer Entertainment. The successor to the PlayStation 2, it is part of the PlayStation brand of consoles. It was first released on Novemb ...

and Microsoft's

Xbox 360 The Xbox 360 is a home video game console developed by Microsoft. As the successor to the original Xbox, it is the second console in the Xbox series. It competed with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generati ...

operating systems. Starting with Mono 2.6, it is possible to configure Mono to use the

LLVM LLVM is a set of compiler and toolchain technologies that can be used to develop a front end for any programming language and a back end for any instruction set architecture. LLVM is designed around a language-independent intermediate repre ...

as the code generation engine instead of Mono's own code generation engine. This is useful for high performance computing loads and other situations where the execution performance is more important than the startup performance. Starting with the Mono 2.7 preview, it is no longer necessary to pick one engine over the other at configuration time. The code generation engine can be selected at startup by using the --llvm or --nollvm command line arguments, and it defaults to the fast-starting Mono code generation engine. Starting with Mono 5.18, support for LLVM is a default configuration option. Previous versions required a special LLVM fork, but now mono can fall back to its own code generator when it encounters something not handled by LLVM.

Garbage collector

As of Mono 2.8, the Mono runtime ships with two garbage collectors: a generational collector and the '' Boehm-Demers-Weiser Conservative Garbage Collector''. The Boehm garbage collector could exhibit memory leaks on certain classes of applications, making it unsuitable for some long-running server applications. Mono switched to ''Simple Generational GC'' (SGen-GC) as the default collector in version 3.1.1. The SGen garbage collector has many advantages over a traditional conservative scanner. It uses generational garbage collection where new objects are allocated from a nursery, during the garbage collection cycle, all objects that survived are migrated to an older generation memory pool. The idea being that many objects are transient and can quickly be collected and only a handful of objects are long-term objects that live for the entire life of the application. To improve performance this collector assigns memory pools to each thread to let threads allocate new memory blocks without having to coordinate with other threads. Migration of objects from the nursery to the old generation is done by copying the data from the nursery to the old generation pool and updating any live pointers that point to the data to point to the new location. This can be expensive for large objects, so Mono's SGen uses a separate pool of memory for large objects (Large Object Section) and uses a mark-and-sweep algorithm for those objects.

Class library

The ''class library'' provides a comprehensive set of facilities for application development. They are primarily written in C#, but due to the Common Language Specification they can be used by any .NET language. The class library is structured into namespaces, and deployed in shared libraries known as assemblies. Speaking of the .NET Framework is primarily referring to this class library.

Namespaces and assemblies

''Namespaces'' are a mechanism for logically grouping similar classes into a hierarchical structure. This prevents naming conflicts. The structure is implemented using dot-separated words, where the most common top-level namespace is System, such as System.IO and System.Net. There are other top-level namespaces as well, such as Accessibility and Windows. A user can define a namespace by placing elements inside a namespace block. ''Assemblies'' are the physical packaging of the class libraries. These are .dll files, just like (but not to be confused with) Win32 shared libraries. Examples of assemblies are mscorlib.dll, System.dll, System.Data.dll and Accessibility.dll. Namespaces are often distributed among several assemblies and one assembly can be composed of several files.

Common Language Infrastructure and Common Language Specification

The Common Language Infrastructure (CLI) as implemented by the Common Language Runtime (CLR), is implemented by the Mono executable. The runtime compiles and executes .NET applications. The common language infrastructure is defined by the ECMA standard. To run an application, you must invoke the runtime with the relevant parameters. The ''Common Language Specification'' (CLS) is specified in chapter 6 of ECMA-335 and defines the interface to the CLI, such as conventions like the underlying types for Enum. The Mono compiler generates an image that conforms to the CLS. This is the Common Intermediate Language. The Mono runtime takes this image and runs it. The ECMA standard formally defines a library that conforms to the CLS as a framework.

Managed and unmanaged code

Within a native .NET/Mono application, all code is managed; that is, it is governed by the CLI's style of memory management and thread safety. Other .NET or Mono applications can use legacy code, which is referred to as unmanaged, by using the System.Runtime.InteropServices libraries to create C# bindings. Many libraries which ship with Mono use this feature of the CLI, such as Gtk#.

Mono-specific innovations

Mono has innovated in some areas with new extensions to the core C# and CLI specifications: * C# Compiler as a Service (Use the C# compiler as a library). * C# Interactive Shell. *

SIMD Single instruction, multiple data (SIMD) is a type of parallel processing in Flynn's taxonomy. SIMD can be internal (part of the hardware design) and it can be directly accessible through an instruction set architecture (ISA), but it shoul ...

support as part of the Mono.SIMD namespace, where method calls to special vector types are directly mapped to the underlying processor CPU SIMD instructions. * Full static compilation of .NET code (used on Mono/iPhone, Mono/PS3). * Mono coroutines (used to implement micro-threading code and continuations, mostly for game developers). * Assembly injection to live processes. * Use of

as JIT backend. * Cxxi an
CppSharp
direct interop with C++ code and libraries. In addition, Mono is available on a variety of operating systems and architectures.

System requirements

Windows 7, Windows 8, Windows 8.1, Windows 10, macOS or Linux

Related projects

Several projects extend Mono and allow developers to use it in their development environment. These projects include: Cross-platform: * Banshee Media Player (stalled), a cross-platform music media player built with Mono and Gtk# and also a driver of dozens of C#-based libraries and projects for media handling. * Beagle (unmaintained), a search system for Unix systems. * Gecko#, bindings for embedding the layout engine used in Mozilla (

Gecko Geckos are small, mostly carnivorous lizards that have a wide distribution, found on every continent except Antarctica. Belonging to the infraorder Gekkota, geckos are found in warm climates throughout the world. They range from . Geckos a ...

). * Gtk#, C# wrappers around the underlying GTK and

libraries, written in C and available on Linux, MacOS and Windows. * Mono Migration Analyzer (MoMA), a tool which aids Windows .NET developers in finding areas in their code that might not be cross-platform and therefore not work in Mono on Linux and other Unixes. Not upgraded since Mono 2.8 (2013); use Microsoft's .NET Portability Analyzer (dotnet-apiport) instead. *

MonoCross MonoCross is a C# .NET Model-view-controller (MVC) framework where the Model and Controller are shared across platforms and the View is implemented for every specific platform and/or target architecture. It allows the development of both native ...

, a cross-platform

model–view–controller Model–view–controller (MVC) is a software architectural pattern commonly used for developing user interfaces that divide the related program logic into three interconnected elements. This is done to separate internal representations of info ...

design pattern where the Model and Controller are shared across platforms and the Views are unique for each platform for an optimized User Interface. The framework requires Xamarin.iOS and Xamarin.Android. *
MvvmCross
a cross-platform

Model View ViewModel A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure. Models c ...

framework utilizing Xamarin.iOS and Xamarin.Android for developing mobile apps. * MonoDevelop an open-source and cross-platform integrated development environment that supports building applications for ASP.NET, Gtk#, Meego, MonoTouch and Silverlight/Moonlight. *

(discontinued), an implementation of

Silverlight Microsoft Silverlight is a discontinued application framework designed for writing and running rich web applications, similar to Adobe's runtime, Adobe Flash. A plugin for Silverlight is still available for a very small number of browsers. Whi ...

that uses Mono. *

OpenTK OpenTK, also known as The Open Toolkit library, is a C# graphics library superseding the Tao Framework. It provides access to graphics tools contained in OpenGL, OpenCL, and OpenAL to a variety of CLR-based languages (C#, F#, etc.). Particula ...

, a managed binding for OpenGL, OpenCL and OpenAL.
QtSharp
C# bindings for the

Qt framework Qt (pronounced "cute") is cross-platform software for creating graphical user interfaces as well as cross-platform applications that run on various software and hardware platforms such as Linux, Windows, macOS, Android or embedded systems wi ...

. * Resco MobileBusiness, a cross-platform developer solution for mobile clients. * Resco MobileCRM, a cross-platform developer solution for mobile clients synchronized with Microsoft Dynamics CRM. * ServiceStack a high-performance open-source .NET REST web services framework that simplifies the development of XML, JSON and SOAP web services. *

SparkleShare SparkleShare is an open-source cloud storage and file synchronization client app. By default, it uses Git as a storage backend. SparkleShare is comparable to Dropbox, but the cloud storage can be provided by the user's own server, or a hosted s ...

an open-source client software that provides cloud storage and file synchronization services. * Tao (superseded by OpenTK), a collection of graphics and gaming bindings (OpenGL, SDL, GLUT, Cg). * Xwt, a GUI toolkit that maps API calls to native platform calls of the underlying platform, exposing one unified API across different platforms and making possible for the graphical user interfaces to have native look and feel on different platforms. It enables building

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

-based desktop applications that run on multiple platforms, without having to customizing code for different platforms. Xwt API is mapped to a set of native controls on each supported platform. Features that are not available on specific platforms are emulated by using native widgets, which is referred to as hosting in the Xwt context. Xwt was partially used as GUI toolkit (beside GTK#) in the development of the Xamarin Studio. Supported "backend" engines are: WPF engine and Gtk engine (using Gtk#) on

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for se ...

, Cocoa engine (using MonoMac) and Gtk engine (using Gtk#) on

Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lap ...

, and Gtk engine (using Gtk#) on

. macOS: * Cocoa# – wrappers around the native macOS toolkit (

Cocoa Cocoa may refer to: Chocolate * Chocolate * ''Theobroma cacao'', the cocoa tree * Cocoa bean, seed of ''Theobroma cacao'' * Chocolate liquor, or cocoa liquor, pure, liquid chocolate extracted from the cocoa bean, including both cocoa butter an ...

) (deprecated). *

Monobjc Mono is a free and open-source .NET Framework-compatible software framework. Originally by Ximian, it was later acquired by Novell, and is now being led by Xamarin, a subsidiary of Microsoft and the .NET Foundation. Mono can be run on many soft ...

– a set of bindings for macOS programming. *

MonoMac MonoMAC syndrome is a rare autosomal dominant syndrome associated with: monocytopenia, B and NK cell lymphopenia; mycobacterial, viral, fungal, and bacterial opportunistic infections; and virus infection-induced cancers. The disorder often pro ...

– newer bindings for macOS programming, based on the MonoTouch API design. Mobile platforms: * MonoDroid. Mono for the Android operating system. With bindings for the Android APIs. *

MonoTouch Mono is a free and open-source .NET Framework-compatible software framework. Originally by Ximian, it was later acquired by Novell, and is now being led by Xamarin, a subsidiary of Microsoft and the .NET Foundation. Mono can be run on many softwa ...

. Mono for the iPhone, iPad and iPod Touches. With bindings to the iOS APIs. Windows: * MonoTools for Visual Studio A Visual Studio plugin that allows Windows developers to target Linux and macOS right from Visual Studio and integrates with SUSE Studio.

Other implementations

has a version of .NET 2.0 now available only for

Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was release to manufacturing, released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Wind ...

, called the Shared Source CLI (Rotor). Microsoft's

shared source The Shared Source Initiative (SSI) is a source-available software licensing scheme launched by Microsoft in May 2001. The program includes a spectrum of technologies and licenses, and most of its source code offerings are available for download ...

license may be insufficient for the needs of the community (it explicitly forbids commercial use).

Free Software Foundation The Free Software Foundation (FSF) is a 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985, to support the free software movement, with the organization's preference for software being distributed under copyleft ( ...

's decommissioned Portable.NET project.

MonoDevelop

MonoDevelop is a free GNOME

integrated development environment An integrated development environment (IDE) is a software application that provides comprehensive facilities to computer programmers for software development. An IDE normally consists of at least a source code editor, build automation tools ...

primarily designed for C# and other .NET languages such as Nemerle, Boo, and

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...

(via

IKVM.NET IKVM.NET is an implementation of Java for Mono and the Microsoft .NET Framework. IKVM is free software, distributed under the zlib permissive free software license. The original developer, Jeroen Frijters, discontinued work on IKVM in 2015. ...

), although it also supports languages such as C, C++, Python, and Vala. MonoDevelop was originally a port of SharpDevelop to Gtk#, but it has since evolved to meet the needs of Mono developers. The IDE includes class management, built-in help, code completion, Stetic (a GUI designer), project support, and an integrated debugger. The MonoDoc browser provides access to API documentation and code samples. The documentation browser uses wiki-style content management, allowing developers to edit and improve the documentation.

Xamarin.iOS and Xamarin.Android

Xamarin.iOS and Xamarin.Android, both developed by

, are implementations of Mono for iPhone and Android-based smartphones. Previously available only for commercial licensing, after Microsoft's acquisition of Xamarin in 2016, the Mono runtime itself was relicensed under

MIT license The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license comp ...

and both Xamarin.iOS and Xamarin.Android are being made free and open-source.

Xamarin.iOS

Xamarin.iOS (previously named MonoTouch) is a library that allows developers to create C# and .NET based applications that run on the iPhone, iPod and iPad devices. It is based on the Mono framework and developed in conjunction with Novell. Unlike Mono applications, Xamarin.iOS "Apps" are compiled down to machine code targeted specifically at the

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancest ...

iPhone and

iPad The iPad is a brand of iOS and iPadOS-based tablet computers that are developed by Apple Inc., Apple Inc. The iPad was conceived before the related iPhone but the iPhone was developed and released first. Speculation about the development, ...

. This is necessary because the iOS kernel prevents just-in-time compilers from executing on the device. The Xamarin.iOS stack is made up of: * Compilers ** C# from the Mono Project ** Third-party compilers like RemObject's Oxygene can target Xamarin.iOS also * Core .NET libraries * Development SDK: ** Linker – used to bundle only the code used in the final application ** mtouch – the Native compiler and tool used to deploy to the target device ** Interface Builder integration tools * Libraries that bind the native CocoaTouch APIs * Xamarin Studio IDE Xamarin Studio is used as the primary IDE, however additional links to

Xcode Xcode is Apple's integrated development environment (IDE) for macOS, used to develop software for macOS, iOS, iPadOS, watchOS, and tvOS. It was initially released in late 2003; the latest stable release is version 14.2, released on December 13, ...

and the iOS simulator have been written. From April to early September 2010, the future of MonoTouch was put in doubt as Apple introduced new terms for iPhone developers that apparently prohibits them from developing in languages other than C, C++ and

Objective-C Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its NeXT ...

, and the use of a middle layer between the iOS platform and iPhone applications. This made the future of MonoTouch, and other technologies such as

Unity Unity may refer to: Buildings * Unity Building, Oregon, Illinois, US; a historic building * Unity Building (Chicago), Illinois, US; a skyscraper * Unity Buildings, Liverpool, UK; two buildings in England * Unity Chapel, Wyoming, Wisconsin, US; a ...

, uncertain. Then, in September 2010, Apple rescinded this restriction, stating that they were relaxing the language restrictions that they had put in place earlier that year.

Xamarin.Android

Xamarin.Android (formerly known as Mono for Android), initially developed by

and continued by

, is a proprietary implementation of Mono for Android-based smart-phones. It was first released on April 6, 2011. Mono for Android was developed to allow developers to more easily write cross-platform applications that will run on all mobile platforms. In an interview with H-Online, Miguel de Icaza stated, "Our vision is to allow developers to reuse their engine and business logic code across all mobile platforms and swapping out the user interface code for a platform-specific API." In August 2010, a Microsoft spokesman, Tom Hanrahan of Microsoft's Open Source Technology Centre, stated, in reference to the lawsuit filed by Oracle against Google over Android's use of Java, that "The type of action Oracle is taking against Google over Java is not going to happen. If a .NET port to Android was through Mono it would fall under the Microsoft Community Promise Agreement." The Xamarin.Android stack consists of the following components: * Mono runtime * An Android UI designer * Libraries: ** Core .NET class libraries ** Libraries that bind the native Android/Java APIs * SDK tools to package, deploy and debug * Xamarin Studio and Visual Studio 2010 integration to design the UI, remotely debug, and deploy.

License

Mono is

dual license Multi-licensing is the practice of distributing software under two or more different sets of terms and conditions. This may mean multiple different software licenses or sets of licenses. Prefixes may be used to indicate the number of licens ...

d by Xamarin, similar to other products such as Qt and the Mozilla Application Suite. Mono's C# compiler and tools are released under the

GNU General Public License The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general ...

(GPLv2 only) (starting with version 2.0 of Mono, the Mono C# compiler source code is also available under the MIT X11 License), the runtime libraries under the

GNU Lesser General Public License The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own ...

(LGPLv2 only) and the class libraries under the

MIT License The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license comp ...

. These are all

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, n ...

and

open-source license An open-source license is a type of license for computer software and other products that allows the source code, blueprint or design to be used, modified and/or shared under defined terms and conditions. This allows end users and commercial com ...

s and hence Mono is free and

open-source software Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. ...

. The license of the C# compiler was changed from the GPL to the MIT X11 license to allow the compiler code to be reused in a few instances where the GPL would have prevented such: * Mono's Compiler as a Service ** The Mono interactive Shell ** The Mono embeddable C# compiler * Mono's implementation of the C# 4.0 dynamic binder. * MonoDevelop's built-in parser and AST graph On March 18, 2016, Microsoft's acquisition of Xamarin was officially closed. On March 31, 2016, Microsoft announced at

Microsoft Build Microsoft Build (often stylised as ) is an annual conference event held by Microsoft, aimed at software engineers and web developers using Windows, Microsoft Azure and other Microsoft technologies. First held in 2011, it serves as a success ...

that they'll completely re-license Mono under the

even in scenarios where previously a commercial license was necessary, and Microsoft stated that they won't assert any "applicable patents" against parties that are "using, selling, offering for sale, importing, or distributing Mono." It was also announced that Xamarin had contributed the Mono Project to the .NET Foundation.

Mono and Microsoft's patents

Software developed with Mono

Many programs covering a range of applications have been developed using the Mono

application programming interface An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

(API) and C#. Some programs written for the Linux Desktop include

Banshee A banshee ( ; Modern Irish , from sga, ben síde , "woman of the fairy mound" or "fairy woman") is a female spirit in Irish folklore who heralds the death of a family member, usually by screaming, wailing, shrieking, or keening. Her name i ...

, Beagle,

F-Spot F-Spot is a slowly maintained image organizer, designed to provide personal photo management for the GNOME desktop environment. The name is a play on the word F-Stop. History The F-Spot project was started by Ettore Perazzoli and is maintained ...

, Gbrainy,

Docky GNOME Do (often referred to as Do) is a free and open-source application launcher for Linux originally created by David Siegel, and currently maintained by Alex Launi. Like other application launchers, it allows searching for applications and file ...

/ GNOME Do,

MonoTorrent MonoTorrent is a cross-platform .NET Standard 2.0 compatible library which implements the BitTorrent protocol. As a result, MonoTorrent can be compiled and executed on every major operating system, including smart phones, IoT or other mobile d ...

, Pinta, and

Tomboy A tomboy is a term for a girl or a young woman with masculine qualities. It can include wearing androgynous or unfeminine clothing and actively engage in physical sports or other activities and behaviors usually associated with boys or men. W ...

. The program, Logos 5 Bible Study Software (OS X Version), was written for the MacOS. A number of video games, such as '' The Sims 3'' and''

Second Life ''Second Life'' is an online multimedia platform that allows people to create an avatar for themselves and then interact with other users and user created content within a multi player online virtual world. Developed and owned by the San Fr ...

'' (for their

scripting language A scripting language or script language is a programming language that is used to manipulate, customize, and automate the facilities of an existing system. Scripting languages are usually interpreted at runtime rather than compiled. A scripting ...

s),

OpenSimulator OpenSimulator is an open-source server platform originally launched in 2007 for hosting virtual worlds and metaverse environments. It is largely compatible with the virtual world ''Second Life'' but full compatibility is not a design goal. Fea ...

virtual world server, or games built with the

or MonoGame

game engine A game engine is a software framework primarily designed for the development of video games and generally includes relevant libraries and support programs. The "engine" terminology is similar to the term "software engine" used in the software ...

s, also make use of Mono. OpenRA bundles its

Apple Disk Image Apple Disk Image is a disk image format commonly used by the macOS operating system. When opened, an Apple Disk Image is mounted as a volume within the Finder. An Apple Disk Image can be structured according to one of several proprietary disk i ...

and Linux AppImages with Mono essentially removing almost all dependencies from the game.Paul Chote
OpenRA: Playtest 20190825
2019-08-25

References

Citations

Sources

* ''This article incorporates text from Mono'
homepage
which was then under the

GNU Free Documentation License The GNU Free Documentation License (GNU FDL or simply GFDL) is a copyleft license for free documentation, designed by the Free Software Foundation (FSF) for the GNU Project. It is similar to the GNU General Public License, giving readers the r ...

.'' * * * * * * * *

External links

*
MonoTouch
Main Page for the port to Apple Inc.'s hand-held products {{DEFAULTSORT:Mono (software) .NET .NET implementations 2004 software Cross-platform software Novell software Software using the MIT license