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NAME

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

SYNOPSIS

       mono [options] file [arguments...]

       mono-sgen [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  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.

PORTABILITY

       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.

RUNTIME OPTIONS

       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:

              autoreg
                     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

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

              bind-to-runtime-version
                     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.

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

              llvm-path=<PREFIX>
                     Same for the llvm tools 'opt' and 'llc'.

              mtriple=<TRIPLE>
                     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.

              nimt-trampolines=[number]
                     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.

              nodebug
                     Instructs the AOT compiler to not output any debugging information.

              no-direct-calls
                     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 calls.

              dwarfdebug
                     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.

              nrgctx-trampolines=[number]
                     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.

              ntrampolines=[number]
                     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.

              outfile=[filename]
                     Instructs the AOT compiler to save the output to the specified file.

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

              readonly-value=namespace.typename.fieldname=type/value
                     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).

              save-temps,keep-temps
                     Instructs the AOT compiler to keep temporary files.

              soft-debug
                     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.

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

              tool-prefix=<PREFIX>
                     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

              write-symbols
                     Instructs the AOT compiler to emit debug symbol information.

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

       --attach=[options]
              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.

       --debugger-agent=[options]
              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:

              address=host:port
                     Use this option to specify the IP address where your debugger client is listening to.

              loglevel=LEVEL
                     Specifies the diagnostics log level for

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

              server=[y/n]
                     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.

              setpgid=[y/n]
                     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.

              suspend=[y/n]
                     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 connection..

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

       --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.

       --full-aot
              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-project.com/docs/advanced/mono-llvm/

       --nollvm
              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:
                   -O=all,-deadce,-inline
              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

              float32
                     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

       --runtime=VERSION
              Mono supports different runtime versions. The version used depends on the program  that  is  being
              run  or  on its configuration file (named program.exe.config). This option can be used to override
              such autodetection, by forcing a different runtime 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" parameter.

              The following modes are supported:

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

              validil
                     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 Mono.

              verifiable
                     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.

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

       --verify-all
              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).

DEVELOPMENT OPTIONS

       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 time.

              mdb-optimizations
                     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.

       --profile[=profiler[:profiler_args]]
              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.

       --trace[=expression]
              Shows  method  names  as  they  are invoked.  By default all methods are traced.  The trace can be
              customized to include or exclude methods, classes or assemblies.  A trace expression  is  a  comma
              separated  list of targets, each target can be prefixed with a minus sign to turn off a particular
              target.  The words `program', `all' and `disabled' have special meaning.  `program' refers to  the
              main  program being executed, and `all' means all the method calls.  The `disabled' option is used
              to start up with tracing disabled.  It can be enabled at a later point in time in the  program  by
              sending  the  SIGUSR2 signal to the runtime.  Assemblies are specified by their name, for example,
              to trace all calls in the System assembly, use:

                   mono --trace=System app.exe

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

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

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

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

              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

       --no-x86-stack-align
              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.

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

                   HEXADDR HEXSIZE methodname

              Currently this option is only supported on Linux.

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.   You  can  use  it
              also with generics, for example "System.Collections.Generic.Queue`1:Peek"

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

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

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

       --graph=TYPE METHOD
              This generates a postscript file with  a  graph  with  the  details  about  the  specified  method
              (namespace.name:methodname).   This  requires  `dot'  and  ghostview  to  be installed (it expects
              Ghostview to be called "gv").  The following graphs are available:
                        cfg        Control Flow Graph (CFG)
                        dtree      Dominator Tree
                        code       CFG showing code
                        ssa        CFG showing code after SSA translation
                        optcode    CFG showing code after IR optimizations
              Some graphs will only be available if certain optimizations are turned on.

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

ATTACH SUPPORT

       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 invocation.

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

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 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 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 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).

LOG PROFILER

       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) page.

CUSTOM PROFILERS

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

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

            mono --profile=custom program.exe

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

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

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

DEBUGGING AIDS

       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

DEBUGGING WITH LLDB

       If you are using LLDB, you can use the mono.py 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/mono.py

       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()

SERIALIZATION

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

       You can control this with the MONO_XMLSERIALIZER_THS environment 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

       LVM_COUNT
              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.

       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_ASPNET_INHIBIT_SETTINGSMAP
              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/settings.map file and, optionally, in the settings.map 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 taken.

       MONO_ASPNET_WEBCONFIG_CACHESIZE
              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).

       MONO_CAIRO_DEBUG_DISPOSE
              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 origin.

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

       MONO_COM
              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.

       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_CPU_ARCH
              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 ...

       MONO_ARM_FORCE_SOFT_FLOAT
              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.

       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 culture-sensitive collation). It internally disables managed  collation  functionality  invoked
              via the members of System.Globalization.CompareInfo class. Collation is enabled by default.

       MONO_DISABLE_SHM
              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.

       MONO_DISABLE_SHARED_AREA
              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.

       MONO_DNS
              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 parallel.

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

       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_ENABLE_SHM
              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.

       MONO_ENV_OPTIONS
              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.

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

       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
                     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).

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

       MONO_GC_PARAMS
              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 words.

              nursery-size=size
                     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 default.

              soft-heap-limit=size
                     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.

              evacuation-threshold=threshold
                     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.

              (no-)lazy-sweep
                     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.

              (no-)concurrent-sweep
                     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.

              stack-mark=mark-mode
                     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.

              save-target-ratio=ratio
                     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.

              default-allowance-ratio=ratio
                     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.

              minor=minor-collector
                     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.

              alloc-ratio=ratio
                     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.

              promotion-age=age
                     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.

              (no-)cementing
                     Enables or disables cementing.  This can dramatically shorten nursery collection  times  on
                     some benchmarks where pinned objects are referred to from the major heap.

       MONO_GC_DEBUG
              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 production.

              number Sets the debug level to the specified number.

              print-allowance
                     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.

              print-pinning
                     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.

              collect-before-allocs

              check-at-minor-collections
                     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.

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

              check-mark-bits
                     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.

              check-nursery-pinned
                     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.

              xdomain-checks
                     Performs a check to make sure that no references are left to an unloaded AppDomain.

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

              debug-clear-at-tlab-creation
                     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.

              clear-at-gc
                     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.

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

              disable-major
                     Don't do major collections.

              conservative-stack-mark
                     Forces the GC to scan the stack conservatively, even if precise scanning is available.

              no-managed-allocator
                     Disables the managed allocator.

              check-scan-starts
                     If set, does a plausibility check on the scan_starts before and after each collection

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

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

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

              binary-protocol=file
                     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

              nursery-canaries
                     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.

              do-not-finalize
                     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-finalizers
                     Log verbosely around the finalization process to aid debugging.

       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/username/.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 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.

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

       MONO_MANAGED_WATCHER
              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_MESSAGING_PROVIDER
              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:

              Mono.Messaging.RabbitMQ.RabbitMQMessagingProvider,Mono.Messaging.RabbitMQ

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

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

       MONO_PATH
              Provides a search path to the runtime where to look for library
              files.   This is a tool convenient for debugging applications, but
              should not be used by deployed applications as it breaks the assembly
              loader in subtle ways.
              Directories are separated by the platform path separator (colons on unix). Example:
              /home/username/lib:/usr/local/mono/lib
              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
              http://www.mono-project.com/docs/getting-started/application-deployment/

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

       MONO_SHARED_HOSTNAME
              Uses the string value of this variable as a replacement for the host name when creating file names
              in the ".wapi" directory. This helps if the host name of your machine is likely to be changed when
              a mono application is running or if you have a .wapi  directory  shared  among  several  different
              computers.   Mono  typically  uses  the  hostname to create the files that are used to share state
              across multiple Mono processes.  This is done to support home directories  that  might  be  shared
              over the network.

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

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

       MONO_TLS_SESSION_CACHE_TIMEOUT
              The  time,  in  seconds,  that  the  SSL/TLS  session  cache  will  keep it's entry to avoid a new
              negotiation between the client and a server. Negotiation are very CPU intensive so an application-
              specific custom value may prove useful for small embedded systems.  The default is 180 seconds.

       MONO_THREADS_PER_CPU
              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.

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

       MONO_X509_REVOCATION_MODE
              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).

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_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:

              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

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

              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.

              dont-free-domains
                     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).

              dyn-runtime-invoke
                     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 symbols.

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

              explicit-null-checks
                     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.

              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 single thread.

              init-stacks
                     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.

              keep-delegates
                     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.

              reverse-pinvoke-exceptions
                     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.

              no-gdb-backtrace
                     This option will disable the GDB backtrace emitted  by  the  runtime  after  a  SIGSEGV  or
                     SIGABRT in unmanaged code.

              suspend-on-sigsegv
                     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.

              check-pinvoke-callconv
                     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.

       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),
              "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".

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

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

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

       MONO_TRACE_LISTENER
              If set, enables the System.Diagnostics.DefaultTraceListener, which will print the  output  of  the
              System.Diagnostics  Trace  and  Debug classes.  It can be set to a filename, and to Console.Out or
              Console.Error to display output to standard output or 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.

       MONO_WCF_TRACE
              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.

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

       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.

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

       MONO_GENERIC_SHARING
              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.

              collections
                     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.

       MONO_XDEBUG
              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.

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

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

       MONO_CONSERVATIVE_HWCAP
              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.

VALGRIND

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

DTRACE

       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 compilation.

       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

PERMISSIONS

       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

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 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.

       <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/community/help/mailing-lists/

WEB SITE

       http://www.mono-project.com

SEE ALSO

       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: http://www.mono-project.com/docs/advanced/aot/

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

                                                                                                  Mono(Mono 3.0)