Mono open source ECMA CLI, C# and .NET implementation.
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Pull request Compare This branch is 21 commits ahead, 17003 commits behind mono:master.
Latest commit 13b742d Jul 29, 2013 @elijahtaylor Updates on 3.2 branch for NaCl
* update nacl stubs file
* various build fixes to workaround no sgen support
* disable a few more tests
* fix dyncode header
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eglib Don't try to detect strndup on OS X; it is only available on 10.7+. Jun 26, 2013
ikvm-native NaCl runtime fixes Apr 7, 2013
m4 Dist fixes Apr 20, 2011
msvc Update csproj files Jul 2, 2013
nacl Add NaCl build scripts Mar 21, 2013
runtime NaCl runtime fixes Apr 7, 2013
scripts Use 4.0 path when configured with disabled 4.5 profile. Fixes #11233 Mar 20, 2013
support Pass some defines in config.h instead of on the command line. Jun 1, 2013
tools [sgen] Cmdline option to print all entries in sgen-grep-binprot. Apr 2, 2013
ChangeLog Updated the build system Apr 19, 2011
LICENSE Update. Nov 13, 2012 Update csproj generator to work on mac Feb 7, 2013
README fixed broken link to automated build in README Jan 26, 2013
acinclude.m4 Enable dolt on x64/osx. Jun 27, 2013 (1) Made build .NET 4.5 as well. Jun 24, 2012
config.rpath Updates on 3.2 branch for NaCl Aug 21, 2013
mkinstalldirs Add mkinstalldirs Sep 15, 2008 Thu Feb 1 12:29:23 CET 2007 Paolo Molaro <> Feb 1, 2007
monowiz.win32.nsi * monowiz.win32.nsi: normalized line-endings to unix (LF) May 27, 2004


This is Mono.

	1. Installation
	2. Using Mono
	3. Directory Roadmap
	4. git submodules maintenance

1. Compilation and Installation

   a. Build Requirements

	On Itanium, you must obtain libunwind:

	On Solaris, make sure that you used GNU tar to unpack this package, as
	Solaris tar will not unpack this correctly, and you will get strange errors.

	On Solaris, make sure that you use the GNU toolchain to build the software.

	Optional dependencies:

		* libgdiplus

		  If you want to get support for System.Drawing, you will need to get
		  Libgdiplus.    This library in turn requires glib and pkg-config:

			* pkg-config

		    	  Available from:

		  	* glib 2.4

		    	  Available from:

		* libzlib

		  This library and the development headers are required for compression
		  file support in the 2.0 profile.

    b. Building the Software
	If you obtained this package as an officially released tarball,
	this is very simple, use configure and make:

		./configure --prefix=/usr/local
		make install

	Mono supports a JIT engine on x86, SPARC, SPARCv9, S/390,
	S/390x, AMD64, ARM and PowerPC systems.   

	If you obtained this as a snapshot, you will need an existing
	Mono installation.  To upgrade your installation, unpack both
	mono and mcs:

		tar xzf mcs-XXXX.tar.gz
		tar xzf mono-XXXX.tar.gz
		mv mono-XXX mono
		mv mcs-XXX mcs
		cd mono
		./ --prefix=/usr/local

	The Mono build system is silent for most compilation commands.
	To enable a more verbose compile (for example, to pinpoint
	problems in your makefiles or your system) pass the V=1 flag to make, like this:

		 make V=1

    c. Building the software from GIT

	If you are building the software from GIT, make sure that you
	have up-to-date mcs and mono sources:

	   If you are an anonymous user:
		git clone git://

           If you are a Mono contributors with read/write privileges:
	        git clone

	Then, go into the mono directory, and configure:

		cd mono
		./ --prefix=/usr/local

	For people with non-standard installations of the auto* utils and of
	pkg-config (common on misconfigured OSX and windows boxes), you could get
	an error like this:

	./configure: line 19176: syntax error near unexpected token `PKG_CHECK_MODULES(BASE_DEPENDENCIES,' ...

	This means that you need to set the ACLOCAL_FLAGS environment var
	when invoking, like this:

		ACLOCAL_FLAGS="-I $acprefix/share/aclocal" ./ --prefix=/usr/loca
	where $acprefix is the prefix where aclocal has been installed.

	This will automatically go into the mcs/ tree and build the
	binaries there.

	This assumes that you have a working mono installation, and that
	there's a C# compiler named 'mcs', and a corresponding IL
	runtime called 'mono'.  You can use two make variables
	EXTERNAL_MCS and EXTERNAL_RUNTIME to override these.  e.g., you
	can say

	  make EXTERNAL_MCS=/foo/bar/mcs EXTERNAL_RUNTIME=/somewhere/else/mono
	If you don't have a working Mono installation

	If you don't have a working Mono installation, an obvious choice
	is to install the latest released packages of 'mono' for your
	distribution and running; make; make install in the
	mono module directory.

	You can also try a slightly more risky approach: this may not work,
	so start from the released tarball as detailed above.

	This works by first getting the latest version of the 'monolite'
	distribution, which contains just enough to run the 'mcs'
	compiler.  You do this with:

		# Run the following line after ./
		make get-monolite-latest

	This will download and automatically gunzip and untar the
	tarball, and place the files appropriately so that you can then
	just run:

		make EXTERNAL_MCS=${PWD}/mcs/class/lib/monolite/gmcs.exe

	And that will use the files downloaded by 'make get-monolite-latest.

	Testing and Installation

	You can run (part of) the mono and mcs testsuites with the command:

		make check

	All tests should pass.  

	If you want more extensive tests, including those that test the
	class libraries, you need to re-run 'configure' with the
	'--enable-nunit-tests' flag, and try

		make -k check

	Expect to find a few testsuite failures.  As a sanity check, you
	can compare the failures you got with

	You can now install mono with:

		make install

	You can verify your installation by using the mono-test-install
	script, it can diagnose some common problems with Mono's install.

	Failure to follow these steps may result in a broken installation. 

    d. Configuration Options

	The following are the configuration options that someone
	building Mono might want to use:

		Generational GC support: Used to enable or disable the
		compilation of a Mono runtime with the SGen garbage collector.

		On platforms that support it, after building Mono, you
		will have both a mono binary and a mono-sgen binary.
		Mono uses Boehm, while mono-sgen uses the Simple
		Generational GC.

	--with-gc=[boehm, included, sgen, none]

		Selects the default Boehm garbage collector engine to
	  	use, the default is the "included" value.
			This is the default value, and its
	  		the most feature complete, it will allow Mono
		  	to use typed allocations and support the

			It is essentially a slightly modified Boehm GC

			This is used to use a system-install Boehm GC,
			it is useful to test new features available in
			Boehm GC, but we do not recommend that people
			use this, as it disables a few features.

			Disables the inclusion of a garbage


		Controls how Mono should access thread local storage,
	  	pthread forces Mono to use the pthread APIs, while
	  	__thread uses compiler-optimized access to it.

	  	Although __thread is faster, it requires support from
	  	the compiler, kernel and libc.   Old Linux systems do
	  	not support with __thread.

		This value is typically pre-configured and there is no
	  	need to set it, unless you are trying to debug a


		Experimental: Use at your own risk, it is known to
		cause problems with garbage collection and is hard to
	 	reproduce those bugs.

		This controls whether Mono will install a special
	  	signal handler to handle stack overflows.   If set to
	  	"yes", it will turn stack overflows into the
	  	StackOverflowException.  Otherwise when a stack
	  	overflow happens, your program will receive a
	  	segmentation fault.

		The configure script will try to detect if your
	  	operating system supports this.   Some older Linux
	  	systems do not support this feature, or you might want
	  	to override the auto-detection.


		This controls whether `mono' should link against a
	  	static library (libmono.a) or a shared library

		This defaults to yes, and will improve the performance
	  	of the `mono' program. 

		This only affects the `mono' binary, the shared
	  	library will always be produced for
	  	developers that want to embed the runtime in their


		The default value for this is `yes', and it makes Mono
	  	generate code which might be slightly slower on
	  	average systems, but the resulting executable will run
	  	faster under the Xen virtualization system.


		Enable support for GC heaps larger than 3GB.

		This value is set to `no' by default.


		Enable some tweaks to reduce memory usage and disk footprint at
		the expense of some capabilities. Typically this means that the
		number of threads that can be created is limited (256), that the
		maxmimum heap size is also reduced (256 MB) and other such limitations
		that still make mono useful, but more suitable to embedded devices
		(like mobile phones).

		This value is set to `no' by default.


		Controls whether the IKVM JNI interface library is
	  	built or not.  This is used if you are planning on
	  	using the IKVM Java Virtual machine with Mono.

		This defaults to `yes'.


		Whether you want to build the 4.x profile libraries
		and runtime.

	  	It defaults to `yes'.


		Whether you want to generate the Silverlight/Moonlight
		libraries and toolchain in addition to the default
		(1.1 and 2.0 APIs).

		This will produce the `smcs' compiler which will reference
		the Silverlight modified assemblies (mscorlib.dll,
		System.dll, System.Code.dll and System.Xml.Core.dll) and turn
	  	on the LINQ extensions for the compiler.


		Select the GC to use for Moonlight.

			Selects the Boehm Garbage Collector, with the same flags
			as the regular Mono build. This is the default.

			Selects the new SGen Garbage Collector, which provides
			Generational GC support, using the same flags as the
			mono-sgen build.

		This defaults to `boehm'.


		This is used to configure where should Mono look for
	  	libgdiplus when running the System.Drawing tests.

		It defaults to `installed', which means that the
	  	library is available to Mono through the regular
	  	system setup.

		`sibling' can be used to specify that a libgdiplus
	  	that resides as a sibling of this directory (mono)
	  	should be used.

		Or you can specify a path to a libgdiplus.


		Use this option to disable the use of shared memory in
		Mono (this is equivalent to setting the MONO_DISABLE_SHM
		environment variable, although this removes the feature

		Disabling the shared memory support will disable certain
		features like cross-process named mutexes.


		Use this feature to specify optional runtime
	  	components that you might not want to include.  This
	  	is only useful for developers embedding Mono that
	  	require a subset of Mono functionality.

		The list is a comma-separated list of components that
	  	should be removed, these are:

			Disables support for the Ahead of Time

			Support for the Mono.Management assembly and the
			VMAttach API (allowing code to be injected into
			a target VM)

			Disables COM support.

			Drop debugging support.

			Disables support for System.Decimal.

			By default Mono comes with a full table
			of messages for error codes.   This feature
			turns off uncommon error messages and reduces
			the runtime size.

			Generics support.  Disabling this will not
			allow Mono to run any 2.0 libraries or
			code that contains generics.

			Removes the JIT engine from the build, this reduces
			the executable size, and requires that all code
			executed by the virtual machine be compiled with
			Full AOT before execution.

			Disables support for large assemblies.

	  		Disables support for debug logging.

			Support for Platform Invocation services,
			disabling this will drop support for any
			libraries using DllImport.

			Removes support for MONO_IOMAP, the environment
			variables for simplifying porting applications that 
			are case-insensitive and that mix the Unix and Windows path separators.

			Disables support for the default profiler.

			Drop System.Reflection.Emit support

			Drop support for saving dynamically created
			assemblies (AssemblyBuilderAccess.Save) in

			Disables support for AppDomain's shadow copies
			(you can disable this if you do not plan on 
			using appdomains).

			Disables support for the Mono.SIMD intrinsics

			Disables compilation for the SSA optimization
			framework, and the various SSA-based


		This enables the use of LLVM as a code generation engine
		for Mono.  The LLVM code generator and optimizer will be 
		used instead of Mono's built-in code generator for both
		Just in Time and Ahead of Time compilations.

		See the for the 
		full details and up-to-date information on this feature.

		You will need to have an LLVM built that Mono can link

		The --enable-loadedllvm variant will make the llvm backend
		into a runtime-loadable module instead of linking it directly
		into the main mono binary.


		This enables the use arrays whose indexes are larger
		than Int32.MaxValue.   

		By default Mono has the same limitation as .NET on
		Win32 and Win64 and limits array indexes to 32-bit
		values (even on 64-bit systems).

		In certain scenarios where large arrays are required,
		you can pass this flag and Mono will be built to
		support 64-bit arrays.

		This is not the default as it breaks the C embedding
		ABI that we have exposed through the Mono development


		Use this option to enable the garbage collector to use
		multiple CPUs to do its work.  This helps performance
		on multi-CPU machines as the work is divided across CPUS.

		This option is not currently the default as we have
		not done much testing with Mono.


		On Solaris and MacOS X builds a version of the Mono
		runtime that contains DTrace probes and can
		participate in the system profiling using DTrace.


		Mono uses /dev/random to obtain good random data for
	  	any source that requires random numbers.   If your
	  	system does not support this, you might want to
	  	disable it.

		There are a number of runtime options to control this
	  	also, see the man page.


		This configures the Mono compiler to generate code
		suitable to be used by Google's Native Client:

		Currently this is used with Mono's AOT engine as
		Native Client does not support JIT engines yet.

2. Using Mono

	Once you have installed the software, you can run a few programs:

	* runtime engine

		mono program.exe

	* C# compiler

		mcs program.cs

	* CIL Disassembler

		monodis program.exe

	See the man pages for mono(1), mint(1), monodis(1) and mcs(2)
	for further details.

3. Directory Roadmap

		Technical documents about the Mono runtime.

		Configuration files installed as part of the Mono runtime.

		The core of the Mono Runtime.

			The object system and metadata reader.

			The Just in Time Compiler.

			CIL executable Disassembler

			Common code for the JIT and the interpreter.

			The I/O layer and system abstraction for 
			emulating the .NET IO model.

			Common Intermediate Representation, XML
			definition of the CIL bytecodes.

			Interpreter for CLI executables (obsolete).

			Architecture specific portions.


		Manual pages for the various Mono commands and programs.


		Some simple sample programs on uses of the Mono
		runtime as an embedded library.   


		Scripts used to invoke Mono and the corresponding program.


		A directory that contains the Makefiles that link the
		mono/ and mcs/ build systems.


		If the directory ../olive is present (as an
		independent checkout) from the Mono module, that
		directory is automatically configured to share the
		same prefix than this module gets.

4. Git submodules maintenance

Read documentation at