mcs, gmcs, smcs - Mono C# Compiler (1.0, 2.0, Moonlight)
mcs [option] [source-files]
mcs is the Mono C# compiler, an implementation of the ECMA-334 language specification. You can pass one or more options to drive the compiler, and a set of source files. Extra options or arguments can be provided in a response file. Response files are referenced by prepending the @ symbol to the response file name.
The mcs compiler is used to compile against the 1.x profile and imple‐ ments C# 1.0 and 2.0 with the exception of generics and nullable types.
The gmcs compiler is used to compile against the 2.0 profile and imple‐ ments the complete C# 2.0 specification including generics.
The smcs compiler is used to compile against the Silverlight/Moonlight profile. This profile is designed to be used for creating Sil‐ verlight/Moonlight applications that will run on a web browser. The API exposed by this profile is a small subset of the 2.0 API (even if it is commonly referred as the 2.1 API, this API is a small subset of 2.0 with a few extensions), in addition this profile by default runs with -langversion:linq which turns on the C# 3.0 language by default.
The Mono C# compiler accepts the same command line options that the Microsoft C# compiler does. Those options can start with a slash or a dash (/checked is the same as -checked). Additionally some GNU-like options are supported, those begin with "--". All MCS-specific flags which are not available in the Microsoft C# compiler are available only with the GNU-style options.
C# source files must end with a ".cs" extension. Compilation of C# source code requires all the files that make up a library, module or executable to be provided on the command line. There is no support for partial compilation. To achieve the benefits of partial compilation, you should compile programs into their own assemblies, and later refer‐ ence them with the "-r" flag.
The Mono C# compiler generates images (.exe files) that contain CIL byte code that can be executed by any system that implements a Common Language Infrastructure virtual machine such as the Microsoft .NET run‐ time engine on Windows or the Mono runtime engine on Unix systems. Executables are not bound to a specific CPU or operating system.
The Mono C# compiler by default only references three assemblies: mscorlib.dll, System.dll and System.Xml.dll. If you want to reference extra libraries you must manually specify them using the -pkg: command line option or the -r: command line option. Alternatively if you want to get all of the System libraries, you can use the -pkg:dotnet command line option.
--about Displays information about the Mono C# compiler
--addmodule:MODULE1[,MODULE2] Includes the specified modules in the resulting assembly.
-checked, -checked+ Sets the default compilation mode to `checked'. This makes all the math operations checked (the default is unchecked).
-checked- Sets the default compilation mode to `unchecked'. This makes all the math operations unchecked (this is the default).
-codepage:ID Specifies the code page used to process the input files from the point it is specified on. By default files will be processed in the environment-dependent native code page. The compiler will also automatically detect Unicode files that have an embedded byte mark at the beginning. Other popular encodings are 28591 (Latin1), 1252 (iso-8859-1) and 65001 (UTF-8). MCS supports a couple of shorthands: "utf8" can be used to specify utf-8 instead of using the cryptic 65001 and "reset" restores the automatic handling of code pages. These shorthands are not available on the Microsoft compiler.
-define:SYMLIST, -d:SYMLIST Defines the symbol listed by the semi-colon separated list SYM‐ LIST SYMBOL. This can be tested in the source code by the pre- processor, or can be used by methods that have been tagged with the Conditional attribute.
-debug, -debug+, -g Generate debugging information. To obtain stack traces with debugging information, you need to invoke the mono runtime with the `--debug' flag. This debugging information is stored inside the assembly as a resource.
-debug- Do not generate debugging information.
-delaysign+ Only embed the strongname public key into the assembly. The actual signing must be done in a later stage using the SN tool. This is useful to protect the private key during development. Note that delay signing can only be done using a strongname key file (not a key container). The option is equivalent to includ‐ ing [assembly: AssemblyDelaySign (true)] in your source code. Compiler option takes precedence over the attributes.
-delaysign- Default. Strongname (sign) the assembly using the strong name key file (or container). The option is equivalent to including [assembly: AssemblyDelaySign (false)] in your source code. Com‐ piler option takes precedence over the attributes.
-doc:FILE Extracts the C#/XML documentation from the source code and stores in in the given FILE.
--expect-error X L The compiler will expect the code to generate an error named `X' in line `L'. This is only used by the test suite.
--fatal This is used for debugging the compiler. This makes the error emission generate an exception that can be caught by a debugger.
-keyfile:KEYFILE Strongname (sign) the output assembly using the key pair present in the specified strong name key file (snk). A full key pair is required by default (or when using delaysign-). A file containing only the public key can be used with delaysign+. The option is equivalent to including [assembly: AssemblyKeyFile ("KEYFILE")] in your source code. Compiler option takes prece‐ dence over the attributes.
-keycontainer:CONTAINER Strongname (sign) the output assembly using the key pair present in the specified container. Note that delaysign+ is ignored when using key containers. The option is equivalent to including [assembly: AssemblyKeyName ("CONTAINER")] in your source code. Compiler option takes precedence over the attributes.
-langversion:TEXT The option specifies the version of the language to use. The feature set is different in each C# version. This switch can be used to force the compiler to allow only a subset of the fea‐ tures. The possible values are:
Default Instruct compiler to use the latest version. Equivalent is to omit the switch (this currently defaults to the C# 2.0 language specification).
ISO-1 Restrict compiler to use only first ISO standardized fea‐ tures. The usage of features such as generics, static classes, anonymous methods will lead to error.
ISO-2 Restrict compiler to use only the second ISO standardized features. This allows the use of generics, static classes, iterators and anonymous methods for example.
linq This enables the C# 3.0 support. Only a few features of C# 3.0 have been implemented in the Mono C# compiler, so not everything is available.
Notice that this flag only controls the language features avail‐ able to the programmer, it does not control the kind of assem‐ blies produced. Programs compiled with mcs will reference the 1.1 APIs, Programs compiled with gmcs reference the 2.0 APIs.
-lib:PATHLIST Each path specified in the comma-separated list will direct the compiler to look for libraries in that specified path.
-L PATH Directs the compiler to look for libraries in the specified path. Multiple paths can be provided by using the option multi‐ ple times.
-main:CLASS Tells the compiler which CLASS contains the entry point. Useful when you are compiling several classes with a Main method.
-nostdlib, -nostdlib+ Use this flag if you want to compile the core library. This makes the compiler load its internal types from the assembly being compiled.
-noconfig, -noconfig+ Disables the default compiler configuration to be loaded. The compiler by default has references to the system assemblies.
-nowarn:WARNLIST Makes the compiler ignore warnings specified in the comma-sepa‐ rated list WARNLIST>
-optimize, -optimize+, -optimize- Controls whether to perform optimizations on the code. -opti‐ mize and -optimize+ will turn on optimizations, -optimize- will turn it off. The default in mcs is to optimize+.
-out:FNAME, -o FNAME Names the output file to be generated.
--parse Used for benchmarking. The compiler will only parse its input files.
-pkg:package1[,packageN] Reference assemblies for the given packages. The compiler will invoke pkg-config --libs on the set of packages specified on the command line to obtain libraries and directories to compile the code. This is typically used with third party components, like this:
$ mcs -pkg:gtk-sharp demo.cs
-pkg:dotnet This will instruct the compiler to reference the System.* libraries available on a typical dotnet framework instal‐ lation, notice that this does not include all of the Mono libraries, only the System.* ones. This is a convenient shortcut for those porting code.
-pkg:olive Use this to reference the "Olive" libraries (the 3.0 and 3.5 extended libraries).
-pkg:silver References the assemblies for creating Moonlight/Sil‐ verlight applications. This is automatically used when using the smcs compiler, but it is here when developers want to use it with the gmcs compiler.
-pkg:silverdesktop Use this option to create Moonlight/Silverlight applica‐ tions that target the desktop. This option allows developers to consume the Silverlight APIs with the full 2.0 profile API available to them, unlike smcs it gives full access to all the APIs that are part of Mono. The only downside is that applications created with sil‐ verdesktop will not run on the browser. Typically these applications will be launched with the mopen command line tool.
-resource:RESOURCE[,ID] Embeds to the given resource file. The optional ID can be used to give a different name to the resource. If not specified, the resource name will be the file name.
-linkresource:RESOURCE[,ID] Links to the specified RESOURCE. The optional ID can be used to give a name to the linked resource.
-r:ASSEMBLY1[,ASSEMBLY2], -r ASSEMBLY1[,ASSEMBLY2] Reference the named assemblies. Use this to use classes from the named assembly in your program. The assembly will be loaded from either the system directory where all the assemblies live, or from the path explicitly given with the -L option.
You can also use a semicolon to separate the assemblies instead of a comma.
-recurse:PATTERN, --recurse PATTERN Does recursive compilation using the specified pattern. In Unix the shell will perform globbing, so you might want to use it like this:
$ mcs -recurse:'*.cs'
--stacktrace Generates a stack trace at the time the error is reported, use‐ ful for debugging the compiler.
-target:KIND, -t:KIND Used to specify the desired target. The possible values are: exe (plain executable), winexe (Windows.Forms executable), library (component libraries) and module (partial library).
--timestamp Another debugging flag. Used to display the times at various points in the compilation process.
-unsafe, -unsafe+ Enables compilation of unsafe code.
-v Debugging. Turns on verbose yacc parsing.
-v2 Turns on C# 2.0 language features.
--version Shows the compiler version.
-warnaserror, -warnaserror+ Treat warnings as errors.
-warn:LEVEL Sets the warning level. 0 is the lowest warning level, and 4 is the highest. The default is 2.
-win32res:FILE Specifies a Win32 resource file (.res) to be bundled into the resulting assembly.
-win32icon:FILE Attaches the icon specified in FILE on the output into the resulting assembly.
-- Use this to stop option parsing, and allow option-looking param‐ eters to be passed on the command line.
The TRACE and DEBUG defines have a special meaning to the compiler.
By default calls to methods and properties in the System.Diagnos‐ tics.Trace class are not generated unless the TRACE symbol is defined (either through a "#define TRACE") in your source code, or by using the --define TRACE in the command line.
By default calls to methods and properties in the System.Diagnos‐ tics.Debug class are not generated unless the DEBUG symbol is defined (either through a "#define DEBUG") in your source code, or by using the --define DEBUG in the command line.
Note that the effect of defining TRACE and DEBUG is a global setting, even if they are only defined in a single file.
When using the "-debug" flag, MCS will generate a file with the exten‐ sion .mdb that contains the debugging information for the generated assembly. This file is consumed by the Mono debugger (mdb).
During compilation the MCS compiler defines the __MonoCS__ symbol, this can be used by pre-processor instructions to compile Mono C# compiler specific code. Please note that this symbol is only to test for the compiler, and is not useful to distinguish compilation or deployment platforms.
The Mono C# Compiler was written by Miguel de Icaza, Ravi Pratap, Mar‐ tin Baulig, Marek Safar and Raja Harinath. The development was funded by Ximian, Novell and Marek Safar.
The Mono Compiler Suite is released under the terms of the GNU GPL. Please read the accompanying `COPYING' file for details. Alternative licensing for the compiler is available from Novell.
mdb(1), mono(1), mopen(1), mint(1), sn(1)
To report bugs in the compiler, you must file them on our bug tracking system, at: http://www.mono-project.com/Bugs
The Mono Mailing lists are listed at http://www.mono-project.com/Mail‐ ing_Lists
The Mono C# compiler was developed by Novell, Inc (http://www.nov‐ ell.com, http) and is based on the ECMA C# language standard available here: http://www.ecma.ch/ecma1/STAND/ecma-334.htm
The home page for the Mono C# compiler is at http://www.mono- project.com/CSharp_Compiler
6 January 2001 mcs(1)