Provided by: mono-runtime-common_4.2.1.102+dfsg2-7ubuntu4_amd64 bug


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


       mono [options] file [arguments...]

       mono-sgen [options] file [arguments...]


       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 the 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
       developing and debugging, and for testing and debugging the runtime itself.

       The mono command uses the Boehm conservative garbage collector while the mono-sgen command
       uses a moving and generational garbage collector.


       On Unix-based systems, Mono provides a mechanism to emulate the Windows-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.


       The following options are available:

       --aot, --aot[=options]
              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  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 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
              available on the generated file.  When precompiling code, you might want to compile
              with  all  optimizations (-O=all).  Pre-compiled code is position independent 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.   AOT  code  typically  can  not be moved from one computer to another (CPU-
              specific optimizations that are detected at runtime) so you should not try to  move
              the   pre-generated   assemblies   or  package  the  pre-generated  assemblies  for
              deployment.  A few options are available as a parameter to the --aot  command  line
              option.   The options are separated by commas, and more than one can be specified:

                     The AOT compiler will emit a (ELF only) library initializer to automatically
                     register the aot compiled module with the runtime.  This is only  useful  in
                     static mode

                     Instructs  the  AOT  compiler  to  output assembly code instead of an object

                     If specified, forces the generated AOT files to  be  bound  to  the  runtime
                     version  of the compiling Mono.   This will prevent the AOT files from being
                     consumed  by  a  different  Mono  runtime.   full  This  is   currently   an
                     experimental  feature  as  it  is  not  complete.   This  instructs  Mono to
                     precompile code that has historically not been precompiled with AOT.

                     When this option is specified, P/Invoke methods are invoked directly instead
                     of going through the operating system symbol lookup operation.

                     Same for the llvm tools 'opt' and 'llc'.

                     Use  the  GNU style target triple <TRIPLE> to determine some code generation
                     options, i.e.  --mtriple=armv7-linux-gnueabi will generate code that targets
                     ARMv7.  This  is  currently only supported by the ARM backend. In LLVM mode,
                     this triple is passed on to the LLVM llc compiler.

                     When compiling in full aot mode, the IMT trampolines must be  precreated  in
                     the  AOT  image.   You  can  add  additional  method  trampolines  with this
                     argument.  Defaults to 128.

                     Instructs the AOT compiler to not output any debugging information.

                     This prevents the AOT compiler from generating a direct calls to  a  method.
                     The  AOT compiler usually generates direct calls for certain methods that do
                     not require going through the PLT (for example, methods that  are  known  to
                     not  require  a hook like a static constructor) or call into simple internal

                     Instructs the AOT compiler to emit DWARF debugging  information.  When  used
                     together  with  the  nodebug  option,  only  DWARF  debugging information is
                     emitted, but not the information that can be used at runtime.

                     When compiling in full aot mode, the generic  sharing  trampolines  must  be
                     precreated in the AOT image.  You can add additional method trampolines with
                     this argument.  Defaults to 1024.

                     When compiling in full aot mode, the method trampolines must  be  precreated
                     in  the  AOT  image.   You  can  add additional method trampolines with this
                     argument.  Defaults to 1024.

                     Instructs the AOT compiler to save the output to the specified file.

                     If the AOT compiler cannot compile a method for any  reason,  enabling  this
                     flag will output the skipped methods to the console.

                     Override  the  value  of  a  static  readonly  field.  Usually,  during  JIT
                     compilation, the static constructor is ran eagerly, so the value of a static
                     readonly field is known at compilation time and the compiler can do a number
                     of optimizations based on it. During AOT, instead,  the  static  constructor
                     can't  be  ran,  so this option can be used to set the value of such a field
                     and enable the same set of optimizations.  Type can be any of i1, i2, i4 for
                     integers  of  the  respective  sizes  (in bytes).  Note that signed/unsigned
                     numbers do not matter here, just the  storage  size.   This  option  can  be
                     specified  multiple  times and it doesn't prevent the static constructor for
                     the type defining the field to execute  with  the  usual  rules  at  runtime
                     (hence possibly computing a different value for the field).

                     Instructs the AOT compiler to keep temporary files.

                     This  instructs  the  compiler  to generate sequence point checks that allow
                     Mono's soft debugger to debug applications even on systems where it  is  not
                     possible   to   set   breakpoints   or  to  single  step  (certain  hardware
                     configurations like the cell phones and video gaming consoles).

              static Create an ELF object file (.o) or .s file which  can  be  statically  linked
                     into  an  executable  when  embedding  the mono runtime. When this option is
                     used, the object file needs to be registered with the embedded runtime using
                     the  mono_aot_register_module  function  which  takes  as  its  argument the
                     mono_aot_module_<ASSEMBLY NAME>_info global symbol from the object file:

                     extern void *mono_aot_module_hello_info;

                     mono_aot_register_module (mono_aot_module_hello_info);

              stats  Print various stats collected during AOT compilation.

                     This is an experimental option for the AOT compiler to use multiple  threads
                     when compiling the methods.

                     Prepends  <PREFIX>  to  the  name  of  tools  ran  by the AOT compiler, i.e.
                     'as'/'ld'. For example, --tool=prefix=arm-linux-gnueabi- will make  the  AOT
                     compiler run

                     Instructs the AOT compiler to emit debug symbol information.

              For more information about AOT, see:

              Currently  the only option supported by this command line argument is disable which
              disables the attach functionality.

       --config filename
              Load the specified configuration file instead of the default one(s).   The  default
              files  are  /etc/mono/config  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.

              This  instructs the Mono runtime to start a debugging agent inside the Mono runtime
              and connect it to a client user interface will  control  the  Mono  process.   This
              option is typically used by IDEs, like the MonoDevelop IDE.

       The configuration is specified using one of more of the following options:

                     Use  this  option  to  specify  the IP address where your debugger client is
                     listening to.

                     Specifies the diagnostics log level for

                     Used to specify the file where the  log  will  be  stored,  it  defaults  to
                     standard output.

                     Defaults  to  no,  with the default option Mono will actively connect to the
                     host/port configured with the address option.  If you  set  it  to  'y',  it
                     instructs  the  Mono  runtime  to start debugging in server mode, where Mono
                     actively waits for the debugger front end to connect to  the  Mono  process.
                     Mono will print out to stdout the IP address and port where it is listening.

                     If  set to yes, Mono will call setpgid(0, 0) on startup, if that function is
                     available on the system. This is useful for ensuring that signals  delivered
                     to  a  process  that  is  executing  the  debuggee are not propagated to the
                     debuggee, e.g. when Ctrl-C sends SIGINT to the sdb tool.

                     Defaults to yes, with the default option Mono will suspend the vm on startup
                     until  it  connects  successfully to a debugger front end.  If you set it to
                     'n', in conjunction with server=y, it instructs the Mono runtime to  run  as
                     normal,  while  caching  metadata  to  send  to  the  debugger  front end on

                     This is used to  specify  the  transport  that  the  debugger  will  use  to
                     communicate.    It  must  be  specified  and  currently  requires this to be

              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.

              This is an experimental flag that instructs the Mono runtime to  not  generate  any
              code  at  runtime  and  depend  exclusively  on  the code generated from using mono
              --aot=full previously.   This is useful for platforms that do  not  permit  dynamic
              code  generation.   Notice  that  this feature will abort execution at runtime if a
              codepath in your program, or Mono's  class  libraries  attempts  to  generate  code
              dynamically.   You  should test your software upfront and make sure that you do not
              use any dynamic features.

       --gc=boehm, --gc=sgen
              Selects the Garbage Collector engine for Mono to use,  Boehm  or  SGen.   Currently
              this  merely  ensures  that  you are running either the mono or mono-sgen commands.
              This flag can be set in the MONO_ENV_OPTIONS environment variable to force  all  of
              your child processes to use one particular kind of GC with the Mono runtime.

       --help, -h
              Displays usage instructions.

       --llvm If  the  Mono  runtime  has  been  compiled with LLVM support (not available in all
              configurations), Mono will use the LLVM optimization and code generation engine  to
              JIT   or   AOT   compile.    For   more   information,   consult:  http://www.mono-

              When using a Mono that has been compiled with  LLVM  support,  it  forces  Mono  to
              fallback to its JIT engine and not use the LLVM backend.

       --optimize=MODE, -O=MODE
              MODE  is a comma separated list of optimizations.  They also allow optimizations to
              be turned off by prefixing the optimization name with a minus  sign.   In  general,
              Mono has been tuned to use the default set of flags, before using these flags for a
              deployment setting, you might want to actually measure the benefits of using  them.
              The following optimization flags are implemented in the core engine:
                           abcrem     Array bound checks removal
                           all        Turn on all optimizations
                           aot        Usage of Ahead Of Time compiled code
                           branch     Branch optimizations
                           cfold      Constant folding
                           cmov       Conditional moves [arch-dependency]
                           deadce     Dead code elimination
                           consprop   Constant propagation
                           copyprop   Copy propagation
                           fcmov      Fast x86 FP compares [arch-dependency]
                           float32     Perform 32-bit float arithmetic using 32-bit operations
                           gshared    Enable generic code sharing.
                           inline     Inline method calls
                           intrins    Intrinsic method implementations
                           linears    Linear scan global reg allocation
                           leaf       Leaf procedures optimizations
                           loop       Loop related optimizations
                           peephole   Peephole postpass
                           precomp    Precompile all methods before executing Main
                           sched      Instruction scheduling
                           shared     Emit per-domain code
                           sse2       SSE2 instructions on x86 [arch-dependency]
                           tailc      Tail recursion and tail calls
              For example, to enable all the optimization but dead code elimination and inlining,
              you can use:
              The flags that are flagged with [arch-dependency] indicate that the given option if
              used  in combination with Ahead of Time compilation (--aot flag) would produce pre-
              compiled code that will depend on the current CPU and might not be safely moved  to
              another computer.

              The following optimizations are supported

                     Requests  that  the  runtime performn 32-bit floating point operations using
                     only 32-bits.   By default  the  Mono  runtime  tries  to  use  the  highest
                     precision  available  for  floating  point  operations, but while this might
                     render better results, the  code  might  run  slower.    This  options  also
                     affects the code generated by the LLVM backend.

              inline Controls  whether the runtime should attempt to inline (the default), or not
                     inline methods invocations

              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
              version 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. The new code verifier can be enabled with this option as well.

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

              The following modes are supported:

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

                     Enables the new verifier and performs basic verification for code  validity.
                     In  this  mode,  unsafe  code and P/Invoke are allowed. This mode provides a
                     better safety guarantee but it is still possible for managed code  to  crash

                     Enables  the  new  verifier and performs full verification of the code being
                     executed.  It only allows verifiable code to be executed.   Unsafe  code  is
                     not  allowed  but  P/Invoke  is.  This mode should not allow managed code to
                     crash mono.  The verification is not as strict as ECMA 335 standard in order
                     to stay compatible with the MS runtime.

              The  security  system  acts  on user code: code contained in mscorlib or the global
              assembly cache is always trusted.

              Configures  the  virtual  machine  to  be  better  suited  for  server   operations
              (currently, allows a heavier threadpool initialization).

              Verifies mscorlib and assemblies in the global assembly cache for valid IL, and all
              user code for IL verifiability.

              This is different from --security's verifiable or validil  in  that  these  options
              only  check  user  code  and  skip  mscorlib  and  assemblies located on the global
              assembly cache.

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


       The following options are used to help when developing a JITed application.

       --debug, --debug=OPTIONS
              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.

              The optional OPTIONS argument is a  comma  separated  list  of  debugging  options.
              These  options are turned off by default since they generate much larger and slower
              code at runtime.

              The following options are supported:

              casts  Produces a detailed  error  when  throwing  a  InvalidCastException.    This
                     option  needs to be enabled as this generates more verbose code at execution

                     Disable some JIT optimizations which are usually only disabled when  running
                     inside  the  debugger.   This  can  be  helpful if you want to attach to the
                     running process with mdb.

              gdb    Generate and register debugging information with gdb. This is only supported
                     on some platforms, and only when using gdb 7.0 or later.

              Turns  on  profiling.   For  more information about profiling applications and code
              coverage see the sections "PROFILING" and "CODE COVERAGE" below.

       This option can be used multiple times, each time will load an
              additional profiler.   This allows developers to use modules that  extend  the  JIT
              through the Mono profiling interface.

              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

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

              Exceptions can also be traced, it will cause a stack trace to be printed every time
              an exception of the specified type is thrown.  The exception type can be  specified
              with  or  without  the namespace, and to trace all exceptions, specify 'all' as the
              type name.

                   mono --trace=E:System.Exception 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

              You can trace managed to unmanaged transitions using the wrapper qualifier:

                   mono --trace=wrapper app.exe

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

                   mono --trace=N:System.Xml

              Don't  align  stack  frames on the x86 architecture.  By default, Mono aligns stack
              frames to 16 bytes on x86, so that local floating point and SIMD variables  can  be
              properly  aligned.   This  option  turns off the alignment, which usually saves one
              intruction per call, but might result in significantly  lower  floating  point  and
              SIMD performance.

              Generate  a JIT method map in a /tmp/ file. This file is then used, for
              example, by the perf tool included in recent Linux kernels.  Each line in the  file

                   HEXADDR HEXSIZE methodname

              Currently this option is only supported on Linux.


       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.  You can use it  also  with  generics,  for  example

              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 (, this is used  for  testing  the
              compiler performance or to examine the output of the code generator.

              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  (   This  requires  `dot'  and  ghostview  to be
              installed (it expects Ghostview to be  called  "gv").   The  following  graphs  are
                        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.

              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.

              Displays  information about the work done by the runtime during the execution of an

              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.).


       The  Mono  runtime  allows  external  processes  to  attach  to a running process and load
       assemblies into the running program.   To attach to the process,  a  special  protocol  is
       implemented in the Mono.Management assembly.

       With  this  support  it  is possible to load assemblies that have an entry point (they are
       created with -target:exe or -target:winexe) to be loaded and executed in the Mono process.

       The code is loaded into the root domain, and it starts execution on  the  special  runtime
       attach  thread.     The  attached  program  should create its own threads and return after

       This support allows for example debugging applications by having the csharp  shell  attach
       to running processes.


       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:


       Mono has a built-in profiler called 'default' (and is also the default if no arguments are
       specified), but developers 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

            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 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).


       This is the most advanced profiler.

       The Mono log profiler can be used to collect a lot of information about a program  running
       in  the Mono runtime.  This data can be used (both while the process is running and later)
       to do analyses of the program behaviour, determine resource usage, performance  issues  or
       even look for particular execution patterns.

       This  is  accomplished  by  logging  the  events  provided by the Mono runtime through the
       profiling interface and periodically writing them to a file which can be  later  inspected
       with the mprof-report(1) tool.

       More  information  about  how  to use the log profiler is available on the mprof-report(1)


       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
       `'.   This  profiler  module must be on your dynamic linker library

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

       Custom profiles are written as shared libraries.  The shared library must be called `mono-' 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.


       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-

       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.

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


       To debug managed applications, you can use the mdb command, a command line debugger.

       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 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 guaranteed and the application might crash or terminate at any
       given point afterwards.

       The --debug=casts option can be used to get more detailed  information  for  Invalid  Cast
       operations, it will provide information about the types involved.

       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), "security" (e.g. Moonlight CoreCLR support) 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


       If  you  are  using  LLDB,  you  can  use  the script to print some internal data
       structures with it.   To use this, add this to your $HOME/.lldbinit file:
       command script import $PREFIX/lib/mono/lldb/

       Where $PREFIX is the prefix value that you used when you configured Mono (typically /usr).

       Once this is done, then you can inspect some Mono Runtime data structures, for example:
       (lldb) p method

       (MonoMethod *) $0 = 0x05026ac0 [mscorlib]System.OutOfMemoryException:.ctor()


       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

       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).


              Turns off the garbage collection in Mono.  This should be only used  for  debugging

              When  Mono  is compiled with LLVM support, this instructs the runtime to stop using
              LLVM after the specified number of methods are JITed.   This  is  a  tool  used  in
              diagnostics  to help isolate problems in the code generation backend.   For example
              LLVM_COUNT=10 would only compile 10 methods with LLVM and then switch to  the  Mono
              JIT engine.  LLVM_COUNT=0 would disable the LLVM engine altogether.

              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 contains a feature which  allows  modifying  settings  in  the  .config  files
              shipped  with  Mono  by  using  config section mappers. The mappers and the mapping
              rules are defined in the $prefix/etc/mono/2.0/ file and, optionally, in
              the file found in the top-level directory of your ASP.NET application.
              Both files are read by System.Web on application startup, if they are found at  the
              above  locations.  If  you  don't want the mapping to be performed you can set this
              variable in your environment before starting the application and no action will  be

              Mono  has  a cache of ConfigSection objects for speeding up WebConfigurationManager
              queries. Its default size is 100 items, and  when  more  items  are  needed,  cache
              evictions  start  happening.  If  evictions  are  too  frequent  this  could impose
              unnecessary overhead, which could be avoided by using this environment variable  to
              set up a higher cache size (or to lower memory requirements by decreasing it).

              If  set,  causes  Mono.Cairo to collect stack traces when objects are allocated, so
              that the finalization/Dispose warnings include  information  about  the  instance's

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

              Sets the style of COM interop.  If the value of this variable is "MS" Mono will use
              string  marhsalling  routines  from  the liboleaut32 for the BSTR type library, any
              other values will use the mono-builtin BSTR string marshalling.

              If  set,  this  variable  overrides  the   default   runtime   configuration   file
              ($PREFIX/etc/mono/config).   The   --config  command  line  options  overrides  the
              environment variable.

              Override the automatic cpu detection mechanism. Currently used only  on  arm.   The
              format of the value is as follows:

                   "armvV [thumb[2]]"

              where  V  is the architecture number 4, 5, 6, 7 and the options can be currently be
              "thumb" or "thumb2". Example:

                   MONO_CPU_ARCH="armv4 thumb" mono ...

              When Mono is built with a soft float fallback on ARM and this variable  is  set  to
              "1", Mono will always emit soft float code, even if a VFP unit is detected.

              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

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

              Unix only: 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 "--disable-shared-handles" option to configure.  This is the
              default from mono 2.8 onwards.

              Unix  only:  If  set,  disable  usage  of  shared  memory  for exposing performance
              counters. This means it will not be possible to both  externally  read  performance
              counters from this processes or read those of external processes.

              When  set,  enables  the use of a fully managed DNS resolver instead of the regular
              libc functions. This resolver performs much better when multiple queries are run in

              Note that /etc/nsswitch.conf will be ignored.

              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

              Unix  only:  Enable  support  for cross-process handles.  Cross-process handles are
              used to expose process handles, thread handles, named  mutexes,  named  events  and
              named semaphores across Unix processes.

              This  environment  variable  allows  you  to  pass command line arguments to a Mono
              process through the environment.   This is useful for example to force all of  your
              Mono processes to use LLVM or SGEN without having to modify any launch scripts.

              Used  to  pass  extra  options  to  the debugger agent in the runtime, as they were
              passed using --debugger-agent=.

              Sets the type of event  log  provider  to  use  (for  System.Diagnostics.EventLog).
              Possible values are:

                     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\ventlog" 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).

              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  general  if  you  have  problems  with
              encodings in your filenames you should use the "convmv" program.

              When  using  Mono  with  the  SGen garbage collector this variable controls several
              parameters of the collector.  The variable's value is a  comma  separated  list  of

                     Sets  the size of the nursery.  The size is specified in bytes and must be a
                     power of two.  The suffixes `k', `m' and `g' can be used to  specify  kilo-,
                     mega-  and gigabytes, respectively.  The nursery is the first generation (of
                     two).  A larger nursery will usually speed up the program but will obviously
                     use more memory.  The default nursery size 4 MB.

              major=collector Specifies which major collector to use.
                     Options  are  `marksweep' for the Mark&Sweep collector, and `marksweep-conc'
                     for concurrent Mark&Sweep.  The non-concurrent Mark&Sweep collector  is  the

                     Once the heap size gets larger than this size, ignore what the default major
                     collection trigger metric says and only allow four nursery size's  of  major
                     heap growth between major collections.

                     Sets  the evacuation threshold in percent.  This option is only available on
                     the Mark&Sweep major collectors.  The value must be an integer in the  range
                     0  to  100.   The default is 66.  If the sweep phase of the collection finds
                     that the occupancy  of  a  specific  heap  block  type  is  less  than  this
                     percentage,  it will do a copying collection for that block type in the next
                     major collection, thereby restoring occupancy to close to  100  percent.   A
                     value of 0 turns evacuation off.

                     Enables  or  disables  lazy sweep for the Mark&Sweep collector.  If enabled,
                     the sweeping of individual major heap blocks is done piecemeal whenever  the
                     need arises, typically during nursery collections.  Lazy sweeping is enabled
                     by default.

                     Enables or disables concurrent  sweep  for  the  Mark&Sweep  collector.   If
                     enabled,  the  iteration  of all major blocks to determine which ones can be
                     freed and which ones have to be kept and swept, is  done  concurrently  with
                     the running program.  Concurrent sweeping is enabled by default.

                     Specifies  how  application threads should be scanned. Options are `precise`
                     and `conservative`. Precise marking allow the collector to know what  values
                     on  stack are references and what are not.  Conservative marking threats all
                     values as potentially references and leave them untouched.  Precise  marking
                     reduces  floating garbage and can speed up nursery collection and allocation
                     rate, it has the downside  of  requiring  a  significant  extra  memory  per
                     compiled method. The right option, unfortunately, requires experimentation.

                     Specifies  the target save ratio for the major collector. The collector lets
                     a given amount of memory to be  promoted  from  the  nursery  due  to  minor
                     collections  before  it triggers a major collection. This amount is based on
                     how much memory it expects to free. It is represented as a ratio of the size
                     of the heap after a major collection.  Valid values are between 0.1 and 2.0.
                     The default is 0.5.  Smaller values will keep the major  heap  size  smaller
                     but  will  trigger  more major collections. Likewise, bigger values will use
                     more memory and result in less frequent major collections.  This  option  is
                     EXPERIMENTAL, so it might disappear in later versions of mono.

                     Specifies  the  default allocation allowance when the calculated size is too
                     small. The allocation allowance is how much  memory  the  collector  let  be
                     promoted  before triggered a major collection.  It is a ratio of the nursery
                     size.  Valid values are between 1.0 and 10.0. The default is  4.0.   Smaller
                     values lead to smaller heaps and more frequent major collections.  Likewise,
                     bigger values will allow the heap to grow faster but use more memory when it
                     reaches  a  stable size.  This option is EXPERIMENTAL, so it might disappear
                     in later versions of mono.

                     Specifies which minor collector to use. Options are 'simple' which  promotes
                     all  objects  from  the  nursery  directly to the old generation and 'split'
                     which lets object stay longer on the nursery before promoting.

                     Specifies the ratio of memory from the nursery to be use by the alloc space.
                     This only can only be used with the split minor collector.  Valid values are
                     integers between 1 and 100. Default is 60.

                     Specifies the required age of an object must reach inside the nursery before
                     been  promoted  to  the  old generation. This only can only be used with the
                     split minor collector.  Valid values are integers between 1 and 14.  Default
                     is 2.

                     Enables  or  disables  cementing.   This  can  dramatically  shorten nursery
                     collection times on some benchmarks where pinned  objects  are  referred  to
                     from the major heap.

              When  using  Mono  with the SGen garbage collector this environment variable can be
              used to turn on various debugging features of the collector.   The  value  of  this
              variable  is  a  comma  separated  list  of  words.   Do  not  use these options in

              number Sets the debug level to the specified number.

                     After each major collection prints memory consumption for before  and  after
                     the  collection and the allowance for the minor collector, i.e. how much the
                     heap is allowed to  grow  from  minor  collections  before  the  next  major
                     collection is triggered.

                     Gathers  statistics  on  the classes whose objects are pinned in the nursery
                     and for which global remset entries are added.  Prints those statistics when
                     shutting down.


                     This  performs  a consistency check on minor collections and also clears the
                     nursery at collection  time,  instead  of  the  default,  when  buffers  are
                     allocated  (clear-at-gc).    The consistency check ensures that there are no
                     major to minor references that are not on the remembered sets.

                     Checks that the mod-union cardtable  is  consistent  before  each  finishing
                     major  collection  pause.  This check is only applicable to concurrent major

                     Checks that mark bits in the major heap are consistent at the  end  of  each
                     major  collection.   Consistent  mark bits mean that if an object is marked,
                     all objects that it had references to must also be marked.

                     After nursery collections, and before starting concurrent collections, check
                     whether  all  nursery  objects  are  pinned,  or  not  pinned - depending on
                     context.  Does nothing when the split nursery collector is used.

                     Performs a check to make sure that no references are  left  to  an  unloaded

                     Clears  the  nursery  incrementally when the thread local allocation buffers
                     (TLAB) are created.  The default setting clears  the  whole  nursery  at  GC

                     Clears  the  nursery  incrementally when the thread local allocation buffers
                     (TLAB) are created, but at GC time fills it  with  the  byte  `0xff`,  which
                     should  result  in  a crash more quickly if `clear-at-tlab-creation` doesn't
                     work properly.

                     This clears the nursery at GC time instead of doing it when the thread local
                     allocation buffer (TLAB) is created.  The default is to clear the nursery at
                     TLAB creation time.

                     Don't do minor collections.  If the nursery is full, a major  collection  is
                     triggered instead, unless it, too, is disabled.

                     Don't do major collections.

                     Forces  the GC to scan the stack conservatively, even if precise scanning is

                     Disables the managed allocator.

                     If set, does a plausibility check on the scan_starts before and  after  each

                     If  set,  does  a  complete  object walk of the nursery at the start of each
                     minor collection.

                     If set, dumps the contents of  the  nursery  at  the  start  of  each  minor
                     collection. Requires verify-nursery-at-minor-gc to be set.

                     Dumps   the  heap  contents  to  the  specified  file.    To  visualize  the
                     information, use the mono-heapviz tool.

                     Outputs the debugging output to the specified file.   For this to work, Mono
                     needs to be compiled with the BINARY_PROTOCOL define on sgen-gc.c.   You can
                     then use this command to explore the output
                                     sgen-grep-binprot 0x1234 0x5678 < file

                     If set, objects allocated in the nursery are suffixed with a canary  (guard)
                     word, which is checked on each minor collection. Can be used to detect/debug
                     heap corruption issues.

                     If enabled, finalizers will not be run.  Everything else will be unaffected:
                     finalizable objects will still be put into the finalization queue where they
                     survive until they're scheduled to finalize.  Once they're not in the  queue
                     anymore they will be collected regularly.

                     Log verbosely around the finalization process to aid debugging.

              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:

              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:

                   export MONO_IOMAP

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

                   MonoIOMAP <appalias> all

              See mod_mono(8) for more details.

              Additionally. Mono includes a profiler  module  which  allows  one  to  track  what
              adjustements  to  file  paths IOMAP code needs to do. The tracking code reports the
              managed location (full stack trace) from which the IOMAP-ed call was made  and,  on
              process  exit, the locations where all the IOMAP-ed strings were created in managed
              code. The latter report is only  approximate  as  it  is  not  always  possible  to
              estimate  the  actual  location  where the string was created. The code uses simple
              heuristics - it analyzes stack trace leading back to the string allocation location
              and ignores all the managed code which lives in assemblies installed in GAC as well
              as in the class libraries shipped with Mono (since they are assumed to be  free  of
              case-sensitivity  issues).  It then reports the first location in the user's code -
              in most cases this will be the place where the string is allocated or very close to
              the  location.  The  reporting code is implemented as a custom profiler module (see
              the "PROFILING" section) and can be loaded in the following way:

                   mono --profile=iomap yourapplication.exe

              Note, however, that Mono currently supports only one profiler module at a time.

              When Mono is using the LLVM code generation backend you can  use  this  environment
              variable to pass code generation options to the LLVM compiler.

              If   set  to  "disabled",  System.IO.FileSystemWatcher  will  use  a  file  watcher
              implementation which silently ignores all the watching requests.   If  set  to  any
              other   value,   System.IO.FileSystemWatcher   will   use   the   default   managed
              implementation (slow). If unset, mono will try to use inotify, FAM,  Gamin,  kevent
              under  Unix  systems  and  native API calls on Windows, falling back to the managed
              implementation on error.

              Mono supports a plugin model for its implementation of System.Messaging  making  it
              possible  to  support a variety of messaging implementations (e.g. AMQP, ActiveMQ).
              To specify which messaging implementation is to be used  the  evironement  variable
              needs  to be set to the full class name for the provider.  E.g. to use the RabbitMQ
              based AMQP implementation the variable should be set to:


              If set causes the mono process to be bound to a single processor. This may be
              useful when debugging or working around race conditions.

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

              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:
              Relative paths are resolved based on the launch-time current directory.
              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 application
              deployment, see

              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

              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.

              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

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

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

              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 systems.  The default is 180 seconds.

              The   minimum   number   of   threads   in   the   general   threadpool   will   be
              MONO_THREADS_PER_CPU * number of CPUs. The default value for this variable is 1.

              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.

              Sets  the  revocation  mode  used  when validating a X509 certificate chain (https,
              ftps, smtps...).  The default is 'nocheck', which performs no revocation  check  at
              all.  The  other  possible  values  are  'offline',  which  performs CRL check (not
              implemented yet) and 'online' which uses OCSP and  CRL  to  verify  the  revocation
              status (not implemented yet).


              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.

              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:

                     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

              casts  This option can be used to get more detailed  information  from  InvalidCast
                     exceptions, it will provide information about the types involved.

                     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.

                     This  is  an  Optimization  for  multi-AppDomain applications (most commonly
                     ASP.NET applications).  Due to internal limitations Mono,  Mono  by  default
                     does not use typed allocations on multi-appDomain applications as they could
                     leak memory when a domain is unloaded.  Although this is a fine default, for
                     applications  that  use more than on AppDomain heavily (for example, ASP.NET
                     applications) it is worth trading off the  small  leaks  for  the  increased
                     performance  (additionally,  since ASP.NET applications are not likely going
                     to unload the application domains on production systems, it is  worth  using
                     this feature).

                     Instructs the runtime to try to use a generic runtime-invoke wrapper instead
                     of creating one invoke wrapper.

              gdb    Equivalent to setting the MONO_XDEBUG variable, this emits  symbols  into  a
                     shared  library  as the code is JITed that can be loaded into GDB to inspect

                     Automatically generates sequence points where the IL stack is empty.   These
                     are places where the debugger can set a breakpoint.

                     Makes  the  JIT  generate  an  explicit  NULL check on variable dereferences
                     instead of depending on the operating system to raise a SIGSEGV  or  another
                     form of trap event when an invalid memory location is accessed.

                     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 single thread.

                     Instructs  the  runtime to initialize the stack with some known values (0x2a
                     on x86-64) at the start of a method to assist in debuggin the JIT engine.

                     This option will leak delegate trampolines that are no longer referenced  as
                     to  present  the  user  with  more  information  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.

                     This option will cause mono to abort with a descriptive message when  during
                     stack  unwinding  after  an  exception it reaches a native stack frame. This
                     happens when a managed delegate is passed to native code,  and  the  managed
                     delegate  throws an exception. Mono will normally try to unwind the stack to
                     the first (managed) exception handler, and it will  skip  any  native  stack
                     frames in the process. This leads to undefined behaviour (since mono doesn't
                     know how to process native frames), leaks, and possibly crashes too.

                     This option will disable the GDB backtrace emitted by the  runtime  after  a
                     SIGSEGV or SIGABRT in unmanaged code.

                     This  option  will  suspend  the  program when a native SIGSEGV is received.
                     This is useful for debugging crashes which do not happen under gdb, since  a
                     live process contains more information than a core file.

                     This  option  causes  the runtime to check for calling convention mismatches
                     when using pinvoke, i.e. mixing cdecl/stdcall. It only works on windows.  If
                     a mismatch is detected, an ExecutionEngineException is thrown.

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

              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),  "security"  (e.g.  Moonlight  CoreCLR support) 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".

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

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

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

              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  standard  error,  respectively. If it's set to Console.Out or Console.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.

              This eases WCF diagnostics functionality by simply outputs all  log  messages  from
              WCF  engine  to "stdout", "stderr" or any file passed to this environment variable.
              The log format is the same as usual diagnostic output.

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

              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.

              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 certain

              This environment variable controls the kind of generic sharing used.  This variable
              is used by internal JIT developers and should not be changed in production.  Do not
              use it.  The variable  controls  which  classes  will  have  generic  code  sharing
              enabled.  Permissible values are:

              all    All generated code can be shared.

                     Only  the  classes  in  System.Collections.Generic will have its code shared
                     (this is the default value).

              corlib Only code in corlib will have its code shared.

              none   No generic code sharing will be performed.
       Generic code sharing by default only applies to collections.   The  Mono  JIT  by  default
       turns this on.

              When  the the MONO_XDEBUG env var is set, debugging info for JITted code is emitted
              into a shared library, loadable into gdb. This enables, for example, to see managed
              frame names on gdb backtraces.

              Enables  the  maximum JIT verbosity for the specified method. This is very helpfull
              to diagnose a miscompilation problems of a specific method.

              If set, makes the JIT output information about detected CPU features (such as  SSE,
              CMOV, FCMOV, etc) to stdout.

              If  set,  the  JIT  will not perform any hardware capability detection. This may be
              useful to pinpoint the cause of JIT issues. This is the default when Mono is  built
              as an AOT cross compiler, so that the generated code will run on most hardware.


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


       On some platforms, Mono can expose a  set  of  DTrace  probes  (also  known  as  user-land
       statically defined, USDT Probes).

       They are defined in the file `mono.d'.

       ves-init-begin, ves-init-end
              Begin and end of runtime initialization.

       method-compile-begin, method-compile-end
              Begin  and  end  of method compilation.  The probe arguments are class name, method
              name and signature, and  in  case  of  method-compile-end  success  or  failure  of

       gc-begin, gc-end
              Begin and end of Garbage Collection.

       To verify the availability of the probes, run:
                  dtrace -P mono'$target' -l -c mono


       Mono's  Ping implementation for detecting network reachability can create the ICMP packets
       itself without requiring the system ping command to do the work.  If you  want  to  enable
       this on Linux for non-root users, you need to give the Mono binary special permissions.

       As root, run this command:
          # setcap cap_net_raw=+ep /usr/bin/mono


       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.

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

       /etc/mono/config, ~/.mono/config
              Mono runtime configuration file.  See  the  mono-config(5)  manual  page  for  more

       ~/.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.

              Files in this directory allow a user to customize the  configuration  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     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.

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


       Mailing lists are listed at the



       certmgr(1),   csharp(1),   mcs(1),   mdb(1),   monocov(1),   monodis(1),   mono-config(5),
       mozroots(1), mprof-report(1), pdb2mdb(1), xsp(1), mod_mono(8).

       For more information on AOT:

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

                                                                                   Mono(Mono 3.0)