Man mono

Updated: 03/2008 Mono(Mono 1.0)                                                 Mono(Mono 1.0)

NAME mono -  Mono's ECMA-CLI native code generator (Just-in-Time and Ahead-       of-Time)

SYNOPSIS mono [options] file [arguments...]

DESCRIPTION mono is a runtime implementation of the ECMA Common  Language  Infras&#8208; tructure. This can be used to run ECMA and .NET applications.

The runtime contains a native code generator that transforms the Common Intermediate Language into native code.

The code generator can operate in two modes: just in time  compilation (JIT) or  ahead  of time compilation (AOT). Since code can be dynami&#8208; cally loaded, the runtime environment and the JIT are always  present, even if code is compiled ahead of time.

The runtime  loads  the specified file and optionally passes the argu&#8208; ments to it. The file is an ECMA assembly. They typically have a .exe or .dll extension.

The runtime  provides  a  number  of configuration options for running applications, for developing and debugging, and for testing and debug&#8208; ging the runtime itself.

PORTABILITY On Unix-based  systems,  Mono provides a mechanism to emulate the Win&#8208; dows-style file access, this includes providing a case insensitive view of the  file  system,  directory  separator  mapping (from \ to /) and stripping the drive letters.

This functionality is enabled by setting  the  MONO_IOMAP  environment variable to one of all, drive and case.

See the description for MONO_IOMAP in the environment variables section for more details.

RUNTIME OPTIONS The following options are available:

--aot This option is used to precompile the CIL code in the  specified assembly to native code. The generated code is stored in a file with the extension .so. This file will be automatically picked up by the runtime when the assembly is executed.

Ahead-of-Time compilation is most useful if you use it in combi&#8208; nation with the -O=all,-shared flag which enables  all  of  the optimizations in  the  code generator to be performed. Some of             those optimizations are not practical for Just-in-Time  compila&#8208; tion since they might be very time consuming.

Unlike the  .NET  Framework, Ahead-of-Time compilation will not generate domain independent code: it generates  the  same  code that the  Just-in-Time  compiler  would  produce. Since most applications use a single domain, this is fine. If you want to             optimize  the  generated  code  for use in multi-domain applica&#8208; tions, consider using the -O=shared flag.

This pre-compiles the methods, but  the  original  assembly  is              still  required to execute as this one contains the metadata and exception information which is not available on  the  generated file. When precompiling  code, you might want to compile with all optimizations (-O=all). Pre-compiled code is position inde&#8208; pendent code.

Pre compilation  is  just  a  mechanism to reduce startup time, increase code sharing across multiple mono processes and  avoid just-in-time compilation  program  startup costs. The original assembly must still be present, as the  metadata  is  contained there.

For  more   information   about   AOT,   see:  http://www.mono- project.com/AOT

--config filename Load the specified configuration file instead  of  the  default one(s). The default files are /etc/mono/config and ~/.mono/con&#8208; fig or the file specified in the MONO_CONFIG environment  vari&#8208; able, if  set. See the mono-config(5) man page for details on             the format of this file.

--desktop Configures the virtual machine to be better suited for  desktop applications. Currently this  sets  the  GC  system  to avoid expanding the heap as much as possible at the expense of slowing down garbage collection a bit.

--help, -h Displays usage instructions.

--optimize=MODE, -O=MODE MODE is  a  comma  separated  list of optimizations. They also allow optimizations to be turned off by prefixing the optimiza&#8208; tion name with a minus sign.

The following optimizations are implemented: all       Turn on all optimizations peephole  Peephole postpass branch    Branch optimizations inline    Inline method calls cfold     Constant folding consprop  Constant propagation copyprop  Copy propagation deadce    Dead code elimination linears   Linear scan global reg allocation cmov      Conditional moves shared    Emit per-domain code sched     Instruction scheduling intrins   Intrinsic method implementations tailc     Tail recursion and tail calls loop      Loop related optimizations fcmov     Fast x86 FP compares leaf      Leaf procedures optimizations aot       Usage of Ahead Of Time compiled code precomp   Precompile all methods before executing Main abcrem    Array bound checks removal ssapre    SSA based Partial Redundancy Elimination sse2      SSE2 instructions on x86

For example, to enable all the optimization but dead code elimi&#8208; nation and inlining, you can use: -O=all,-deadce,-inline

--runtime=VERSION Mono supports different  runtime  versions. The version  used depends on the program that is being run or on its configuration file (named program.exe.config). This option  can  be  used  to              override such autodetection, by forcing a different runtime ver&#8208; sion to be used. Note that this should only be used to select a              later  compatible  runtime  version than the one the program was compiled against. A typical usage is for running a 1.1  program on a 2.0 version: mono --runtime=v2.0.50727 program.exe

--security, --security=mode Activate the security manager, a currently experimental feature in Mono and it is OFF by default.

Using security without parameters is equivalent as  calling  it              with the "cas" parameter.

The following modes are supported:

cas   This   allows   mono   to  support  declarative  security attributes, e.g. execution of Code Access Security (CAS) or non-CAS demands.

core-clr Enables the core-clr security system, typically used for Moonlight/Silverlight applications. It provides a  much simpler security  system  than CAS, see http://www.mono- project.com/Moonlight for more details and links to  the descriptions of this new system.

--server Configures the  virtual  machine to be better suited for server operations (currently, a no-op).

-V, --version Prints JIT version information (system  configuration,  release              number and branch names if available).

DEVELOPMENT OPTIONS The following options are used to help when developing a JITed applica&#8208; tion.

--debug Turns on the debugging mode in the runtime. If an assembly was compiled with debugging information, it will produce line number information for stack traces.

--profile[=profiler[:profiler_args]] Turns on profiling. For more information about profiling appli&#8208; cations and code coverage see the sections "PROFILING" and "CODE             COVERAGE" below.

--trace[=expression] Shows method names as they are invoked. By default all methods are traced.

The trace  can  be  customized  to  include or exclude methods, classes or assemblies. A trace expression is a comma separated list of  targets, each target can be prefixed with a minus sign to turn off a particular target. The words `program', `all' and `disabled' have  special meaning. `program' refers to the main program being executed, and `all' means all the method calls.

The `disabled' option is used to start up with tracing disabled. It can  be  enabled  at a later point in time in the program by              sending the SIGUSR2 signal to the runtime.

Assemblies are specified by their name, for example,  to  trace all calls in the System assembly, use:

mono --trace=System app.exe

Classes are specified with the T: prefix. For example, to trace all calls to the System.String class, use:

mono --trace=T:System.String app.exe

And individual methods are referenced with the M:  prefix,  and the standard method notation:

mono --trace=M:System.Console:WriteLine app.exe

As previously noted, various rules can be specified at once:

mono --trace=T:System.String,T:System.Random app.exe

You can  exclude  pieces, the next example traces calls to Sys&#8208; tem.String except for the System.String:Concat method.

mono --trace=T:System.String,-M:System.String:Concat

Finally, namespaces can be specified using the N: prefix:

mono --trace=N:System.Xml

JIT MAINTAINER OPTIONS The maintainer options are only used by those developing  the  runtime itself, and not typically of interest to runtime users or developers.

--break method Inserts a  breakpoint  before the method whose name is `method' (namespace.class:methodname). Use `Main'  as  method  name  to              insert a breakpoint on the application's main method.

--breakonex Inserts a  breakpoint  on exceptions. This allows you to debug your application with a native debugger when  an  exception  is              thrown.

--compile name This compiles a method (namespace.name:methodname), this is used for testing the compiler performance or to examine the output of             the code generator.

--compileall Compiles all  the methods in an assembly. This is used to test the compiler performance or to examine the output of  the  code generator

--graph=TYPE METHOD This generates  a postscript file with a graph with the details about the specified method  (namespace.name:methodname). This requires `dot'  and  ghostview  to  be  installed  (it  expects              Ghostview to be called "gv").

The following graphs are available: cfg       Control Flow Graph (CFG) dtree     Dominator Tree code      CFG showing code ssa       CFG showing code after SSA translation optcode   CFG showing code after IR optimizations

Some graphs will only be available if certain optimizations are turned on.

--ncompile Instruct the  runtime  on  the  number of times that the method specified by --compile (or all the methods if  --compileall  is              used) to be compiled. This is used for testing the code genera&#8208; tor performance.

--stats Displays information about the work done by the runtime  during the execution of an application.

--wapi=hps|semdel Perform maintenance of the process shared data.

semdel will delete the global semaphore.

hps will list the currently used handles.

-v, --verbose Increases the verbosity level, each time it is listed, increases the verbosity level to include more information (including, for              example,  a disassembly of the native code produced, code selec&#8208;              tor info etc.).

PROFILING The mono runtime includes a profiler that can be used to explore vari&#8208; ous performance related problems in your application. The profiler is      activated by passing the --profile command line argument  to  the  Mono runtime, the format is:

--profile[=profiler[:profiler_args]]

Mono has a built-in profiler called 'default' (and is also the default       if no arguments are specified), but developers can write custom profil&#8208; ers, see the section "CUSTOM PROFILERS" for more details.

If a profiler is not specified, the default profiler is used.

The profiler_args is a profiler-specific string of options for the pro&#8208; filer itself.

The default profiler accepts the following options 'alloc' to  profile memory consumption by the application; 'time' to profile the time spent on each routine; 'jit' to collect time spent JIT-compiling methods and 'stat' to perform sample statistical profiling. If no options are pro&#8208; vided the default is 'alloc,time,jit'.

By default the profile data is printed to stdout: to change this,  use the 'file=filename' option to output the data to filename.

For example:

mono --profile program.exe

That will  run  the program with the default profiler and will do time and allocation profiling.

mono --profile=default:stat,alloc,file=prof.out program.exe

Will do sample statistical profiling and allocation profiling on  pro&#8208; gram.exe. The profile data is put in prof.out.

Note that  the statistical profiler has a very low overhead and should be the preferred profiler to use (for better output use the full  path       to  the  mono  binary when running and make sure you have installed the       addr2line utility that comes from the binutils package).

PROFILERS There are a number of external profilers that have been developed  for Mono, we will update this section to contain the profilers.

The heap  Shot  profiler can track all live objects, and references to       these objects, and includes a GUI tool, this is  our  recommended  pro&#8208; filer. To install you must download the profiler from Mono's SVN: svn co svn://svn.myrealbox.com/source/trunk/heap-shot cd heap-shot ./autogen make make install

See the included documentation for details on using it.

The Live  Type  profiler  shows  at every GC iteration all of the live objects of a given type. To install you must download  the  profiler from Mono's SVN: svn co svn://svn.myrealbox.com/source/trunk/heap-prof cd heap-prof ./autogen make make install

To use the profiler, execute: mono --profile=desc-heap program.exe

The output of this profiler looks like this: Checkpoint at 102 for heap-resize System.MonoType : 708 System.Threading.Thread : 352 System.String : 3230 System.String[] : 104 Gnome.ModuleInfo : 112 System.Object[] : 160 System.Collections.Hashtable : 96 System.Int32[] : 212 System.Collections.Hashtable+Slot[] : 296 System.Globalization.CultureInfo : 108 System.Globalization.NumberFormatInfo : 144

The first line describes the iteration number for the GC, in this case checkpoint 102.

Then on each line the type is displayed as well as the number of bytes that are being consumed by live instances of this object.

The AOT  profiler is used to feed back information to the AOT compiler about how to order code based on the access patterns for pages. To use it, use: mono --profile=aot program.exe The output of this profile can be fed back into Mono's AOT compiler to       order the functions on the disk to produce precompiled images that have methods in sequential pages.

CUSTOM PROFILERS Mono provides a mechanism for loading other profiling modules which in       the form of shared libraries. These profiling modules can hook up  to       various  parts of the Mono runtime to gather information about the code being executed.

To use a third party profiler you must pass the name of the profiler to      Mono, like this:

mono --profile=custom program.exe

In the  above sample Mono will load the user defined profiler from the shared library `mono-profiler-custom.so'. This profiler module must be      on your dynamic linker library path.

A list of other third party profilers is available from Mono's web site (www.mono-project.com/Performance_Tips)

Custom profiles are written as shared libraries. The shared  library must be called `mono-profiler-NAME.so' where `NAME' is the name of your profiler.

For a sample of how to write your own custom profiler look in the Mono source tree for in the samples/profiler.c.

CODE COVERAGE Mono ships  with  a code coverage module. This module is activated by      using  the  Mono  --profile=cov  option. The  format   is:   --pro&#8208; file=cov[:assembly-name[/namespace]] test-suite.exe

By default code coverage will default to all the assemblies loaded, you can limit this by specifying the assembly name, for example to perform code coverage in the routines of your program use, for example the fol&#8208; lowing command line limits the code coverage to routines in the "demo" assembly:

mono --profile=cov:demo demo.exe

Notice that the assembly-name does not include the extension.

You can  further  restrict  the  code  coverage output by specifying a       namespace:

mono --profile=cov:demo/My.Utilities demo.exe

Which will only perform code coverage in the given assembly and names&#8208; pace.

Typical output looks like this:

Not covered: Class:.ctor Not covered: Class:A Not covered: Driver:.ctor Not covered: Driver:method Partial coverage: Driver:Main offset 0x000a

The offsets displayed are IL offsets.

A more  powerful  coverage  tool is available in the module `monocov'. See the monocov(1) man page for details.

DEBUGGING It is possible to obtain a stack trace of all the  active  threads  in       Mono  by sending the QUIT signal to Mono, you can do this from the com&#8208; mand line, like this:

kill -QUIT pid

Where pid is the Process ID of the Mono process you want  to  examine. The process  will  continue  running  afterwards, but its state is not guaranteed.

Important: this is a last-resort mechanism for debugging  applications and should  not  be used to monitor or probe a production application. The integrity of the runtime after sending this signal is not  guaran&#8208; teed and  the  application might crash or terminate at any given point afterwards.

You can use the MONO_LOG_LEVEL and MONO_LOG_MASK environment variables to get verbose debugging output about the execution of your application within Mono.

The MONO_LOG_LEVEL environment variable if set, the logging  level  is       changed  to  the  set  value. Possible values are "error", "critical", "warning", "message", "info", "debug". The default value  is  "error". Messages with  a  logging level greater then or equal to the log level will be printed to stdout/stderr.

Use "info" to track the dynamic loading of assemblies.

Use the MONO_LOG_MASK environment variable to limit the extent of  the messages you  get:  If  set, the log mask is changed to the set value. Possible values are "asm" (assembly  loader),  "type",  "dll"  (native       library  loader), "gc" (garbage collector), "cfg" (config file loader), "aot" (precompiler) and "all". The default value is  "all". Changing the mask value allows you to display only messages for a certain compo&#8208; nent. You can use multiple masks by comma separating them. For example to see  config file messages and assembly loader messages set you mask to "asm,cfg".

The following is a common use to track down problems with P/Invoke:

$ MONO_LOG_LEVEL="debug" MONO_LOG_MASK="dll" mono glue.exe

SERIALIZATION Mono's XML serialization engine by default will use a reflection-based approach to  serialize  which  might be slow for continuous processing (web service applications). The serialization engine  will  determine when a class must use a hand-tuned serializer based on a few parameters and if needed it will produce a customized C# serializer for your types at runtime. This customized serializer then gets dynamically loaded into your application.

You can control this with the MONO_XMLSERIALIZER_THS environment vari&#8208; able.

The possible  values  are  `no'  to disable the use of a C# customized serializer, or an integer that is the minimum number of uses before the runtime will produce a custom serializer (0 will produce a custom seri&#8208;      alizer on the first access, 50 will produce a serializer  on  the  50th       use). Mono will fallback to an interpreted serializer if the serializer generation somehow fails. This behavior can be disabled by setting the option `nofallback' (for example: MONO_XMLSERIALIZER_THS=0,nofallback).

ENVIRONMENT VARIABLES GC_DONT_GC Turns off the garbage collection in Mono. This should be  only used for debugging purposes

MONO_AOT_CACHE If set,  this variable will instruct Mono to ahead-of-time com&#8208; pile new assemblies on demand and store the result into a cache in ~/.mono/aot-cache.

MONO_CFG_DIR If set, this variable overrides the default system configuration directory ($PREFIX/etc). It's used  to  locate  machine.config file.

MONO_CONFIG If set,  this variable overrides the default runtime configura&#8208; tion file ($PREFIX/etc/mono/config). The --config command  line options overrides the environment variable.

MONO_DEBUG If set,  enables some features of the runtime useful for debug&#8208; ging. This variable should contain a comma separated  list  of              debugging  options. Currently, the following options are sup&#8208; ported:

collect-pagefault-stats Collects information about pagefaults. This is  used internally to track the number of page faults produced to                    load metadata. To display this information you must use this option with "--stats" command line option.

handle-sigint Captures the interrupt signal (Control-C) and displays a                     stack trace when pressed. Useful to find out where  the program is  executing  at a given point. This only dis&#8208; plays the stack trace of a single thread.

keep-delegates This option will leak delegate trampolines that  are  no                     longer referenced as to present the user with more infor&#8208; mation about a delegate misuse. Basically a  delegate instance might be created, passed to unmanaged code, and no references kept in managed code, which  will  garbage collect the  code. With this option it is possible to                     track down the source of the problems.

break-on-unverified If this variable is set, when the Mono VM  runs  into  a                     verification problem, instead of throwing an exception it                     will break into the debugger. This is useful when debug&#8208; ging verifier problems

MONO_DISABLE_AIO If set, tells mono NOT to attempt using native asynchronous I/O services. In that case, a default select/poll implementation is              used. Currently only epoll is supported.

MONO_DISABLE_MANAGED_COLLATION If this  environment variable is `yes', the runtime uses unman&#8208; aged collation (which actually means no culture-sensitive colla&#8208;             tion). It internally  disables managed collation functionality invoked via  the  members  of  System.Globalization.CompareInfo class. Collation is enabled by default.

MONO_EGD_SOCKET For platforms that do not otherwise have a way of obtaining ran&#8208; dom bytes this can be set to the name of a file system socket on             which an egd or prngd daemon is listening.

MONO_EVENTLOG_TYPE Sets the type of event log provider to use (for System.Diagnos&#8208;              tics.EventLog).

Possible values are:

local[:path]

Persists event logs and entries to the local file system.

The directory  in which to persist the event logs, event sources and entries can be  specified  as  part  of  the value.

If the  path  is  not  explicitly  set,  it  defaults to                     "/var/lib/mono/eventlog" on unix  and  "%APPDATA%no\vent&#8208;                     log" on Windows.

win32

Uses the  native win32 API to write events and registers event logs and event sources in the registry. This is                     only available on Windows.

On Unix,  the  directory permission for individual event log and event source directories is set to 777 (with  +t                     bit)  allowing  everyone  to  read  and  write  event log entries while only allowing entries to be deleted by the user(s) that created them.

null

Silently discards any events.

The default  is  "null" on Unix (and versions of Windows before              NT), and "win32" on Windows NT (and higher).

MONO_EXTERNAL_ENCODINGS If set, contains a colon-separated list of text encodings to try when turning externally-generated text (e.g. command-line argu&#8208;              ments or filenames) into Unicode. The encoding names come from the  list   provided   by   iconv,   and   the   special   case "default_locale" which refers to the current  locale's  default encoding.

When reading  externally-generated  text strings UTF-8 is tried first, and then this list is tried in order with the first suc&#8208; cessful conversion  ending  the  search. When writing external text (e.g. new filenames or arguments  to  new  processes)  the first item  in  this  list is used, or UTF-8 if the environment variable is not set.

The problem with using MONO_EXTERNAL_ENCODINGS to process  your files is that it results in a problem: although its possible to              get the right file name it is not necessarily possible  to  open the file. In general  if you have problems with encodings in              your filenames you should use the "convmv" program.

MONO_GAC_PREFIX Provides a prefix the runtime uses to look for Global  Assembly Caches. Directories are separated by the platform path separa&#8208; tor (colons on unix). MONO_GAC_PREFIX should point to  the  top directory of a prefixed install. Or to the directory provided in             the    gacutil    /gacdir    command. Example:   /home/user&#8208; name/.mono:/usr/local/mono/

MONO_IOMAP Enables some filename rewriting support to assist badly-written applications that hard-code Windows paths. Set to a colon-sepa&#8208; rated list  of  "drive" to strip drive letters, or "case" to do              case-insensitive file matching in every  directory  in  a  path. "all" enables  all  rewriting methods. (Backslashes are always             mapped to slashes if this variable is set to a valid option.)

For example, this would work from the shell:

MONO_IOMAP=drive:case export MONO_IOMAP

If you are using mod_mono to host your web applications, you can use the MonoSetEnv directive, like this:

MonoSetEnv MONO_IOMAP=all

MONO_MANAGED_WATCHER If set  to  any value, System.IO.FileSystemWatcher will use the default managed implementation (slow). If unset, mono will  try to use  FAM under Unix systems and native API calls on Windows, falling back to the managed implementation on error.

MONO_NO_SMP If set causes the mono process to be bound to a single  proces&#8208; sor. This may  be useful when debugging or working around race conditions.

MONO_PATH Provides a search path to the runtime where to look for library files. This is a tool convenient for debugging applications, but should not be used by deployed applications as it breaks the assembly loader in subtle ways.

Directories are separated by the platform path separator (colons             on unix). Example: /home/username/lib:/usr/local/mono/lib

Alternative solutions to MONO_PATH include: installing libraries into the  Global  Assembly Cache (see gacutil(1)) or having the dependent libraries side-by-side with the main executable.

For a complete description of recommended practices for applica&#8208; tion  deployment,  see  the  http://www.mono-project.com/Guide&#8208; lines:Application_Deployment page.

MONO_RTC Experimental RTC support in the statistical  profiler:  if  the user has the permission, more accurate statistics are gathered. The MONO_RTC value must be restricted to  what  the  Linux  rtc allows: power  of two from 64 to 8192 Hz. To enable higher fre&#8208; quencies like 4096 Hz, run as root:

echo 4096 > /proc/sys/dev/rtc/max-user-freq

For example:

MONO_RTC=4096 mono --profiler=default:stat program.exe

MONO_NO_TLS Disable inlining of thread local accesses. Try setting this  if              you get a segfault early on in the execution of mono.

MONO_SHARED_DIR If set  its  the  directory  where  the ".wapi" handle state is              stored. This is the directory where the Windows I/O  Emulation layer stores  its  shared  state  data (files, events, mutexes,              pipes). By default Mono will store the ".wapi" directory in the users's home directory.

MONO_SHARED_HOSTNAME Uses the string value of this variable as a replacement for the host name when creating file names in  the  ".wapi"  directory. This helps  if  the  host  name of your machine is likely to be              changed when a mono application is running  or  if  you  have  a              .wapi directory shared among several different computers.

Mono typically  uses  the hostname to create the files that are used to share state across multiple Mono  processes. This is              done  to  support home directories that might be shared over the network.

MONO_STRICT_IO_EMULATION If set, extra checks are made during IO operations. Currently, this includes only advisory locks around file writes.

MONO_DISABLE_SHM If set, disables the shared memory files used for cross-process handles: process have only private handles. This means  that process and thread handles are not available to other processes, and named mutexes, named events and named  semaphores  are  not visible between processes.

This is  can  also be enabled by default by passing the "--dis&#8208;              able-shared-handles" option to configure.

MONO_THEME The name of the theme to be used by Windows.Forms. Available themes today include "clearlooks", "nice" and "win32".

The default is "win32".

MONO_TLS_SESSION_CACHE_TIMEOUT The time,  in seconds, that the SSL/TLS session cache will keep it's entry to avoid a new negotiation between the client and  a              server. Negotiation are  very CPU intensive so an application- specific custom value may prove useful for small embedded  sys&#8208; tems.

The default is 180 seconds.

MONO_THREADS_PER_CPU The maximum number of threads in the general threadpool will be              20 + (MONO_THREADS_PER_CPU * number of CPUs). The default value for this variable is 5.

MONO_XMLSERIALIZER_THS Controls the threshold for the XmlSerializer to produce a custom serializer for a given class instead of using  the  Reflection- based interpreter. The possible values are `no' to disable the use of a custom serializer or a number  to  indicate  when  the XmlSerializer should  start serializing. The default value is             50, which means that the a custom serializer will be produced on              the 50th use.

MONO_XMLSERIALIZER_DEBUG Set this value to 1 to prevent the serializer from removing the temporary files that are created for fast serialization;   This might be useful when debugging.

ENVIRONMENT VARIABLES FOR DEBUGGING

MONO_ASPNET_NODELETE If set to any value, temporary source files generated by ASP.NET support classes will not be removed. They will be kept  in  the user's temporary directory.

MONO_LOG_LEVEL The logging  level,  possible  values  are `error', `critical', `warning', `message', `info' and `debug'. See the  DEBUGGING section for more details.

MONO_LOG_MASK Controls the domain of the Mono runtime that logging will apply to. If set, the log mask is changed to the set value. Possible values are  "asm"  (assembly  loader),  "type",  "dll"  (native              library loader), "gc" (garbage collector),  "cfg"  (config  file              loader),  "aot"  (precompiler)  and "all". The default value is             "all". Changing the mask value allows you to display only  mes&#8208; sages for  a  certain  component. You can use multiple masks by             comma separating them. For example to see config file  messages and assembly loader messages set you mask to "asm,cfg".

MONO_TRACE Used for  runtime  tracing  of  method calls. The format of the comma separated trace options is:

[-]M:method name [-]N:namespace [-]T:class name [-]all [-]program disabled      Trace output off upon start.

You can toggle trace output on/off sending a SIGUSR2 signal  to              the program.

MONO_TRACE_LISTENER If set,  enables  the  System.Diagnostics.DefaultTraceListener, which will print the output of the System.Diagnostics Trace and Debug classes. It can be set to a filename, and to Console.Out or Console.Error to display output to standard output or  stan&#8208; dard error,  respectively. If it's set to Console.Out or Con&#8208; sole.Error you can append an optional prefix that will be  used when writing  messages  like this: Console.Error:MyProgramName. See the  System.Diagnostics.DefaultTraceListener  documentation for more information.

MONO_XEXCEPTIONS This throws  an  exception  when a X11 error is encountered; by              default a message is displayed but execution continues

MONO_XSYNC This is used in the  System.Windows.Forms  implementation  when running with the X11 backend. This is used to debug problems in             Windows.Forms as it forces all  of  the  commands  send  to  X11 server to be done synchronously. The default mode of operation is asynchronous which makes it hard to isolate the root of cer&#8208; tain problems.

MONO_GENERIC_SHARING This environment  variable is completely unsupported, don't use it. This controls for which classes  to  enable  generic  code sharing in  principle. Permissible values are "all", "corlib" and "none". The default is "none", meaning  that  sharing  can only happen for corlib classes. Note that to enable generation of shared code the "gshared" compiler option has to be  set  as              well.

VALGRIND If you want to use Valgrind, you will find the file `mono.supp' useful, it contains the suppressions for the GC which trigger incorrect  warn&#8208; ings. Use it like this: valgrind --suppressions=mono.supp mono ...

FILES On Unix assemblies are loaded from the installation lib directory. If      you set `prefix' to /usr, the assemblies will be located  in  /usr/lib. On Windows, the assemblies are loaded from the directory where mono and mint live.

~/.mono/aot-cache

The directory for the ahead-of-time  compiler  demand  creation assemblies are located.

/etc/mono/config, ~/.mono/config

Mono runtime configuration file. See the mono-config(5) manual page for more information.

~/.config/.mono/certs, /usr/share/.mono/certs

Contains Mono certificate stores for users / machine. See the certmgr(1) manual page for more information on managing certifi&#8208; cate stores and the mozroots(1) page for information on how  to              import  the  Mozilla root certificates into the Mono certificate store.

~/.mono/assemblies/ASSEMBLY/ASSEMBLY.config

Files in this directory allow a user to customize the configura&#8208; tion for  a  given  system  assembly,  the  format  is  the one described in the mono-config(5) page.

~/.config/.mono/keypairs, /usr/share/.mono/keypairs

Contains Mono cryptographic keypairs for users / machine. They can be  accessed  by using a CspParameters object with DSACryp&#8208; toServiceProvider and RSACryptoServiceProvider classes.

~/.config/.isolatedstorage,           ~/.local/share/.isolatedstorage, /usr/share/.isolatedstorage

Contains Mono isolated storage for non-roaming  users,  roaming users and local machine. Isolated storage can be accessed using the classes from the System.IO.IsolatedStorage namespace.

.config

Configuration information for individual assemblies is loaded by             the  runtime from side-by-side files with the .config files, see the http://www.mono-project.com/Config for more information.

Web.config, web.config

ASP.NET applications are configured through  these  files,  the configuration is done on a per-directory basis. For more infor&#8208; mation on this subject see the http://www.mono-project.com/Con&#8208; fig_system.web page.

MAILING LISTS Mailing lists  are  listed  at  the  http://www.mono-project.com/Mail&#8208; ing_Lists

WEB SITE http://www.mono-project.com

SEE ALSO certmgr(1), mcs(1),  monocov(1),  monodis(1),   mono-config(5),   moz&#8208; roots(1), xsp(1).

For more information on AOT: http://www.mono-project.com/AOT

For ASP.NET-related documentation, see the xsp(1) manual page

Mono(Mono 1.0)