1:mono
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mono - Mono's ECMA-CLI native code generator (Just-in-Time and Ahead-of-Time)
mono [options] file [arguments...]
DESCRIPTION
mono is a runtime implementation of the ECMA Common Language Infrastructure. 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 dynamically loaded, the runtime environment and the JIT are always present, even if code is
compiled ahead of time.
The runtime loads ths specified file and optionally passes the arguments 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 developping and debugging,
and for testing and debugging the runtime itself.
PORTABILITY
On Unix-based systems, Mono provides a mechanism to emulate the Windows-style file access, this includes provid-
ing 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 combination 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 compilation since they might be very time consuming.
Unlike the .NET Framework, Ahead-of-Time compilation will not generate domain independent code: it gener-
ates 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 applications,
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 availble on the generated file. When precompiling
code, you might want to compile with all optimizations (-O=all). Pre-compiled code is position indepen-
dent code.
Pre compilation is just a mechanism to reduce startup time, and avoid just-in-time compilation costs. The
original assembly must still be present, as the metadata is contained there.
--config filename
Load the specified configuration file instead of the default one(s). The default files are /etc/mono/con-
fig and ~/.mono/config or the file specified in the MONO_CONFIG environment variable, 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 pre-
fixing the optimization 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
For example, to enable all the optimization but dead code elimination and inlining, you can use:
-O=all,-deadce,-inline
--security
Activate the security manager (experimental feature in 1.1). This allows mono to support declarative secu-
rity attributes (e.g. execution of, CAS or non-CAS, security demands). The security manager is OFF by
default (experimental).
--server
Configures the virtual machine to be better suited for server operations.
-V , --version
Prints JIT version information.
DEVELOPMENT OPTIONS
The following options are used to help when developing a JITed application.
--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 applications 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' and `all' have special meaning. `program' refers to the main program being
executed, and `all' means all the method calls.
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 standar 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 System.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 (names-
pace.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 generator 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 selector info etc.).
PROFILING
The mono runtime includes a profiler that can be used to explore various 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 devel-
opers can write custom profilers, 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 profiler 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 provided 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 program.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 bet-
ter output use the full path to the mono binary when running and make sure you have installed the addr2line util-
ity 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 con-
tain the profilers.
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.
CUSTOM PROFILERS
Mono provides a mechanism for loading other profiling modules which in the form of shared libraries. These pro-
filing modules can hook up to various parts of the Mono runtime to gather information about the code being exe-
cuted.
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: --profile=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 following 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 namespace.
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.
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 command 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 after-
wards.
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 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".
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 continous 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 variable.
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 serializer 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 compile 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 ($PREFIX/etc). It's used to
locate machine.config file.
MONO_CONFIG
If set, this variable overrides the default runtime configuration file ($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 debugging. This variable should contain a comma
separated list of debugging options. Currently, the following options are supported:
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 displays the stack trace of a sin-
gle thread.
keep-delegates
This option will leak delegate trampolines that are no longer referenced as to present the user
with more information about a delegate missuse. 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 debugging 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 unmanaged collation (which actually means no cul-
ture-sensitive collation). 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 random 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.Diagnostics.EventLog).
Possible values are:
local[:path]
Persists event logs and entries to the local file system.
The directory in which to persit 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 "%APP-
DATA%no\ventlog" on Windows.
win32
Uses the native win32 API to write events and registers event logs and event sources in the reg-
istry. 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 arguments 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 successful 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 gen-
eral 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 separator (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-
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-separated 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_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/user-
name/lib:/usr/local/mono/lib
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 frequencies 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 execu-
tion of mono.
MONO_SHARED_DIR
If set its the directory where the ".wapi" handle state is stored. This is the directory where the Win-
dows 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 appli-
cation 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_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_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 seri-
alizer 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 messages for a certain component. You can use
multiple masks by comma separating them. For example to see config file messages and assembly loader mes-
sages 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 Sys-
tem.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 standard error, respectively. If it's set to Console.Out or Con-
sole.Error you can append an optional prefix that will be used when writing messages like this: Con-
sole.Error:MyProgramName. See the System.Diagnostics.DefaultTraceListener documentation for more informa-
tion.
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 syn-
chronously. The default mode of operation is asynchronous which makes it hard to isolate the root of
certain problems.
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 certificate 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 configuration for a given system assembly, the for-
mat 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 DSACryptoServiceProvider 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.
<assembly>.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 information on this subject see the http://www.mono-project.com/Config_system.web page.
MAILING LISTS
Mailing lists are listed at the http://www.mono-project.com/Mailing_Lists
WEB SITE
http://www.mono-project.com
RELATED
certmgr(1),mcs(1),mint(1),monodis(1),mono-config(5),mozroots(1),xsp(1). For ASP.NET-related documentation, see the xsp(1) manual page
Mono(Mono 1.0)