mono

Mono(mono)                                                            Mono(mono)



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 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.

       These executables can reference additional functionality in the form of
       assembly references.  By default those assembly references are resolved
       as follows: the mscorlib.dll is resolved from the system profile that is
       configured by Mono, and other assemblies are loaded from the Global
       Assembly Cache (GAC).

       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 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 moving and generational SGen garbage collector
       while the mono-boehm command uses the conservative Boehm 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.

METHOD DESCRIPTIONS
       A number of diagnostic command line options take as argument a method
       description.   A method description is a textual representation that can
       be used to uniquely identify a method.   The syntax is as follows:
       [namespace]classname:methodname[(arguments)]

       The values in brackets are optional, like the namespace and the
       arguments.   The arguments themselves are either empty, or a comma-
       separated list of arguments.   Both the classname and methodname can be
       set to the special value '*' to match any values (Unix shell users should
       escape the argument to avoid the shell interpreting this).

       The arguments, if present should be a comma separated list of types
       either a full typename, or for built-in types it should use the low-level
       ILAsm type names for the built-in types, like 'void', 'char', 'bool',
       'byte', 'sbyte', 'uint16', 'int16', 'uint',

       Pointer types should be the name of the type, followed by a '*', arrays
       should be the typename followed by '[' one or more commas (to indicate
       the rank of the array), and ']'.

       Generic values should use '<', one or more type names, separated by both
       a comma and a space and '>'.

       By-reference arguments should include a "&" after the typename.

       Examples:
       *:ctor(int)         // All constructors that take an int as an argument
       *:Main              // Methods named Main in any class
       *:Main(string[])    // Methods named Main that take a string array in any class

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.  Precompilation 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:

              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.

              data-outfile=FILE.dll.aotdata
                     This instructs the AOT code generator to output certain
                     data constructs into a separate file.   This can reduce the
                     executable images some five to twenty percent.   Developers
                     need to then ship the resulting aotdata as a resource and
                     register a hook to load the data on demand by using the
                     mono_install_load_aot_data_hook method.

              direct-icalls
                     When this option is specified, icalls (internal calls made
                     from the standard library into the mono runtime code) are
                     invoked directly instead of going through the operating
                     system symbol lookup operation.  This requires use of the
                     static option.

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

              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.

              full   This creates binaries which can be used with the --full-aot
                     option.

              hybrid This creates binaries which can be used with the --hybrid-
                     aot option.

              llvm   AOT will be performed with the LLVM backend instead of the
                     Mono backend where possible. This will be slower to compile
                     but most likely result in a performance improvement.

              llvmonly
                     AOT will be performed with the LLVM backend exclusively and
                     the Mono backend will not be used. The only output in this
                     mode will be the bitcode file normally specified with the
                     llvm-outfile option. Use of llvmonly automatically enables
                     the full and llvm options. This feature is experimental.

              llvmopts=[options]
                     Use this option to add more flags to the built-in set of
                     flags passed to the LLVM optimizer.   When you invoke the
                     mono command with the --aot=llvm it displays the current
                     list of flags that are being passed to the opt command.
                     The list of possible flags that can be passed can be
                     obtained by calling the bundled opt program that comes with
                     Mono, and calling it like this:

                          opt --help



              llvmllc=[options]
                     Use this option to add more flags to the built-in set of
                     flags passed to the LLVM static compiler (llc).   The list
                     of possible flags that can be passed can be obtained by
                     calling the bundled llc program that comes with Mono, and
                     calling it like this:

                          llc --help


              mcpu=[native o generic]
                     cpu=native allows AOT mode to use all instructions current
                     CPU supports, e.g. AVX2, SSE42, etc.  Default value is
                     'generic'.  mattr=[cpu feature] Allows AOT code generator
                     to use specified CPU features where possible including
                     `System.Runtime.Intrinsics.*'.  E.g.
                     `mattr=+avx2,mattr=-lzcnt' unlocks sse1-4.2, avx1-2 and
                     disables lzcnt.  It's useful for cross-compilation or when
                     it's not possible to use `-mcpu=native' (which enables all
                     cpu feature current cpu has).  llvm-outfile=[filename]
                     Gives the path for the temporary LLVM bitcode file created
                     during AOT.  dedup Each AOT module will typically contain
                     the code for inflated methods and wrappers that are called
                     by code in that module. In dedup mode, we identify and skip
                     compiling all of those methods. When using this mode with
                     fullaot, dedup-include is required or these methods will
                     remain missing.

              dedup-include=[filename]
                     In dedup-include mode, we are in the pass of compilation
                     where we compile the methods that we had previously
                     skipped. All of them are emitted into the assembly that is
                     passed as this option. We consolidate the many duplicate
                     skipped copies of the same method into one.


              info   Print the architecture the AOT in this copy of Mono targets
                     and quit.

              interp Generates all required wrappers, so that it is possible to
                     run --interpreter without any code generation at runtime.
                     This option only makes sense with mscorlib.dll.  Embedders
                     can set

              depfile=[filename]
                     Outputs a gcc -M style dependency file.

                     mono_jit_set_aot_mode (MONO_AOT_MODE_INTERP);

              ld-flags
                     Additional flags to pass to the C linker (if the current
                     AOT mode calls for invoking it).

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

              msym-dir=<PATH>
                     Instructs the AOT compiler to generate offline sequence
                     points .msym files.  The generated .msym files will be
                     stored into a subfolder of <PATH> named as the compilation
                     AOTID.

              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 512.

              ngsharedvt-trampolines=[number]
                     When compiling in full aot mode, the value type generic
                     sharing trampolines must be precreated in the AOT image.
                     You can add additional method trampolines with this
                     argument.  Defaults to 512.

              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.

              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 4096.

              nrgctx-fetch-trampolines=[number]
                     When compiling in full aot mode, the generic sharing fetch
                     trampolines must be precreated in the AOT image.  You can
                     add additional method trampolines with this argument.
                     Defaults to 128.

              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 4096.

              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.

              profile=[file]
                     Specify a file to use for profile-guided optimization. See
                     the AOT profiler sub-section. To specify multiple files,
                     include the profile option multiple times.

              profile-only
                     AOT *only* the methods described in the files specified
                     with the profile option. See the AOT profiler sub-section.

              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.

              temp-path=[path]
                     Explicitly specify path to store temporary files created
                     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

              ld-name=NAME
                     One of the tools used for AOT builds is the linker. Its
                     name differs between various systems and it may happen that
                     the assumed default name of the binary is not present.  If
                     the toolchain used does not have a linker with the default
                     name (e.g. Android NDK r22 does not have the default 'ld'
                     linker prefixed with 'tool-prefix' above, instead it has
                     prefixed 'ld.gold' and 'ld.bfd' linkers) this option can be
                     used to set the linker binary name. It will be prefixed
                     with 'tool-prefix' to form the full linker executable name.

              verbose
                     Prints additional information about type loading failures.

              write-symbols,no-write-symbols
                     Instructs the AOT compiler to emit (or not emit) debug
                     symbol information.

              no-opt Instructs the AOT compiler tot no call opt when compiling
                     with LLVM.

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

       --aot-path=PATH
              List of additional directories to search for AOT images.

       --apply-bindings=FILE
              Apply the assembly bindings from the specified configuration file
              when running the AOT compiler.  This is useful when compiling an
              auxiliary assembly that is referenced by a main assembly that
              provides a configuration file.  For example, if app.exe uses
              lib.dll then in order to make the assembly bindings from
              app.exe.config available when compiling lib.dll ahead of time,
              use:
                   mono --apply-bindings=app.exe.config --aot lib.dll

       --assembly-loader=MODE
              If mode is strict, Mono will check that the public key token,
              culture and version of a candidate assembly matches the requested
              strong name.  If mode is legacy, as long as the name matches, the
              candidate will be allowed. strict is the behavior consistent with
              .NET Framework but may break some existing mono-based
              applications.  The default is legacy.

       --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 or Visual Studio IDEs.
              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 flag 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, or if you need to run assemblies that have been
                     stripped of IL (for example using mono-cil-strip).  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.

              --full-aot-interp
                     Same as --full-aot with fallback to the interpreter.

              --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.

              --gc-debug=[options]
                     Command line equivalent of the MONO_GC_DEBUG environment
                     variable.

              --gc-params=[options]
                     Command line equivalent of the MONO_GC_PARAMS environment
                     variable.

              --arch=32, --arch=64
                     (Mac OS X only): Selects the bitness of the Mono binary
                     used, if available. If the binary used is already for the
                     selected bitness, nothing changes. If not, the execution
                     switches to a binary with the selected bitness suffix
                     installed side by side (for example, '/bin/mono --arch=64'
                     will switch to '/bin/mono64' iff '/bin/mono' is a 32-bit
                     build).

              --help, -h
                     Displays usage instructions.

              --interpreter
                     The Mono runtime will use its interpreter to execute a
                     given assembly.  The interpreter is usually slower than the
                     JIT, but it can be useful on platforms where code
                     generation at runtime is not allowed.

              --hybrid-aot
                     This flag allows the Mono runtime to run assemblies that
                     have been stripped of IL, for example using mono-cil-strip.
                     For this to work, the assembly must have been AOT compiled
                     with --aot=hybrid.

                     This flag is similar to --full-aot, but it does not disable
                     the JIT. This means you can use dynamic features such as
                     System.Reflection.Emit.

              --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/

              --ffast-math
                     This flag allows Mono and LLVM to apply aggressive floating
                     point optimizations.  Can break IEEE754 compliance.

              --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
              --response=FILE Provides a response file, this instructs the Mono
              command to read other command line options from the specified
              file, as if the options had been specified on the command line.
              Useful when you have very long command lines.

              --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

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

              --use-map-jit
                     Instructs Mono to generate code using MAP_JIT on MacOS.
                     Necessary for bundled applications.

              --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).

              --version=number
                     Print version number only.



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]]
              Loads a profiler module with the given arguments. For more
              information, see the PROFILING section.  This option can be used
              multiple times; each time will load an additional profiler module.

       --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
              instruction 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.

       --bisect=optimization:filename
              This flag is used by the automatic optimization bug bisector.  It
              takes an optimization flag and a filename of a file containing a
              list of full method names, one per line.  When it compiles one of
              the methods in the file it will use the optimization given, in
              addition to the optimizations that are otherwise enabled.  Note
              that if the optimization is enabled by default, you should disable
              it with `-O`, otherwise it will just apply to every method,
              whether it's in the file or not.

       --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.

       --compile-all
              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 --compile-all is
              used) to be compiled.  This is used for testing the code generator
              performance.

       --stats=[method]
              Displays information about the work done by the runtime during the
              execution of an application. If a method
              (namespace.name:methodname) is specified, it will display that
              information when the method is first run in addition to the end of
              program execution.

       --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 API that dynamically loaded profiler
       modules and embedders can use to collect performance-related data about
       an application. Profiler modules are loaded by passing the --profile
       command line argument to the Mono runtime.

       Mono ships with a few profiler modules, of which the log profiler is the
       most feature-rich. It is also the default profiler if the profiler
       argument is not given, or if default is given.  It is possible to write
       your own profiler modules; see the Custom profilers sub-section.

   Log profiler
       The 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 behavior,
       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 profiler API and periodically writing them to a file which
       can later be inspected with the mprof-report(1) tool.

       More information about how to use the log profiler is available on the
       mono-profilers(1) page, under the LOG PROFILER section, as well as the
       mprof-report(1) page.

   Coverage profiler
       The code coverage profiler can instrument a program to help determine
       which classes, methods, code paths, etc are actually executed. This is
       most useful when running a test suite to determine whether the tests
       actually cover the code they're expected to.

       More information about how to use the coverage profiler is available on
       the mono-profilers(1) page, under the COVERAGE PROFILER section.

   AOT profiler
       The AOT profiler can help improve startup performance by logging which
       generic instantiations are used by a program, which the AOT compiler can
       then use to compile those instantiations ahead of time so that they won't
       have to be JIT compiled at startup.

       More information about how to use the AOT profiler is available on the
       mono-profilers(1) page, under the AOT PROFILER section.

   Custom profilers
       Custom profiler modules can be loaded in exactly the same way as the
       standard modules that ship with Mono. They can also access the same
       profiler API to gather all kinds of information about the code being
       executed.

       For example, to use a third-party profiler called custom, you would load
       it like this:

              mono --profile=custom program.exe

       You could also pass arguments to it:

              mono --profile=custom:arg1,arg2=arg3 program.exe

       In the above example, Mono will load the profiler from the shared library
       called libmono-profiler-custom.so (name varies based on platform, e.g.,
       libmono-profiler-custom.dylib on OS X).  This profiler module must be on
       your dynamic linker library path (LD_LIBRARY_PATH on most systems,
       DYLD_LIBRARY_PATH on OS X).

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

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),
       "threadpool" (thread pool generic), "io-selector" (async socket
       operations), "io-layer" (I/O layer - processes, files, sockets, events,
       semaphores, mutexes and handles), "io-layer-process", "io-layer-file",
       "io-layer-socket", "io-layer-event", "io-layer-semaphore", "io-layer-
       mutex", "io-layer-handle" 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

       HTTP_PROXY
              (Also http_proxy) If set, web requests using the Mono Class
              Library will be automatically proxied through the given URL.  Not
              supported on Windows, Mac OS, iOS or Android. See also NO_PROXY.

       LLVM_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_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_DARWIN_USE_KQUEUE_FSW
              Fall back on the kqueue FileSystemWatcher implementation in
              Darwin. The default is the FSEvent implementation.

       MONO_DARWIN_WATCHER_MAXFDS
              This is a debugging aid used to force limits on the kqueue
              FileSystemWatcher implementation in Darwin.   There is no limit by
              default.

       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_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_AIO
              If set, tells mono to attempt using native asynchronous I/O
              services. If not set, a default select/poll implementation is
              used. Currently epoll and kqueue are supported.

       MONO_THREADS_SUSPEND Selects a mechanism that Mono will use to suspend
              threads.  May be set to "preemptive", "coop", or "hybrid".
              Threads may need to be suspended by the debugger, or using some
              .NET threading APIs, and most commonly when the SGen garbage
              collector needs to stop all threads during a critical phase of
              garbage collection.  Preemptive mode is the mode that Mono has
              used historically, going back to the Boehm days, where the garbage
              collector would run at any point and suspend execution of all
              threads as required to perform a garbage collection.  The
              cooperative mode on the other hand requires the cooperation of all
              threads to stop at a safe point.  This makes for an easier to
              debug garbage collector and it improves the stability of the
              runtime because threads are not suspended when accessing critical
              resources.  In scenarios where Mono is embedded in another
              application, cooperative suspend requires the embedder code to
              follow coding guidelines in order to cooperate with the garbage
              collector.  Cooperative suspend in embedded Mono is currently
              experimental.  Hybrid mode is a combination of the two that
              retains better compatability with scenarios where Mono is embedded
              in another application: threads that are running managed code or
              code that comprises the Mono runtime will be cooperatively
              suspended, while threads running embedder code will be
              preemptively suspended.  Hybrid suspend is the default on some
              desktop platforms.

              Alternatively, coop and hybrid mode can be enabled at compile time
              by using the --enable-cooperative-suspend or --enable-hybrid-
              suspend flags, respectively, when calling configure.  The
              MONO_THREADS_SUSPEND environment variable takes priority over the
              compiled default.

       MONO_ENABLE_COOP_SUSPEND
              This environment variable is obsolete, but retained for backward
              compatibility.  Use MONO_THREADS_SUSPEND set to "coop" instead.
              Note that if configure flags were provided to enable cooperative
              or hybrid suspend, this variable is ignored.

       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_SDB_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.

              max-heap-size=size
                     Sets the maximum size of the heap. 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 limit is the sum of the nursery, major
                     heap and large object heap. Once the limit is reached the
                     application will receive OutOfMemoryExceptions when trying
                     to allocate.  Not the full extent of memory set in max-
                     heap-size could be available to satisfy a single allocation
                     due to internal fragmentation. By default heap limits is
                     disabled and the GC will try to use all available memory.

              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, `marksweep-conc'
                     for concurrent Mark&Sweep and `marksweep-conc-par' for
                     parallel and concurrent Mark&Sweep.  The concurrent
                     Mark&Sweep collector is the default.

              mode=balanced|throughput|pause[:max-pause]
                     Specifies what should be the garbage collector's target.
                     The `throughput' mode aims to reduce time spent in the
                     garbage collector and improve application speed, the
                     `pause' mode aims to keep pause times to a minimum and it
                     receives the argument max-pause which specifies the maximum
                     pause time in milliseconds that is acceptable and the
                     `balanced' mode which is a general purpose optimal mode.

              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, `simple-par' which has same
                     promotion behavior as `simple' but using multiple workers
                     and `split' which lets objects 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.

              allow-synchronous-major
                     This forbids the major collector from performing
                     synchronous major collections.  The major collector might
                     want to do a synchronous collection due to excessive
                     fragmentation. Disabling this might trigger OutOfMemory
                     error in situations that would otherwise not happen.

       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-remset-consistency
                     This performs a remset consistency check at various
                     opportunities, 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-untag
                     After garbage collections, check whether all vtable
                     pointers are no longer tagged.

              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.

              managed-allocator
                     Enables 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. This disables the usage of the managed allocator,
                     because allocation from full aot code is inconsistent with
                     this option. If the application is guaranteed not to use
                     aot code, the managed allocator can be enabled back with
                     managed-allocator option.


              do-not-finalize(=classes)
                     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.  If a list
                     of comma-separated class names is given, only objects from
                     those classes will not be finalized.


              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
              (deprecated) Enabled some filename rewriting support to assist
              badly-written applications that hard-code Windows paths. It no
              longer works as of Mono 6.0.

       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_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_TLS_PROVIDER
              This environment variable controls which TLS/SSL provider Mono will
              use.  The options are usually determined by the operating system where
              Mono was compiled and the configuration options that were used for
              it.

              default
                     Uses the default TLS stack that the Mono runtime was configured with.
                     Usually this is configured to use Apple's SSL stack on Apple
                     platforms, and Boring SSL on other platforms.

              apple  Forces the use of the Apple SSL stack, only works on Apple platforms.

              btls   Forces the use of the BoringSSL stack.    See
                     https://opensource.google.com/projects/boringssl for more information
                     about this stack.

              legacy This is the old Mono stack, which only supports SSL and TLS up to
                     version 1.0.   It is deprecated and will be removed in the future.

       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).

       NO_PROXY
              (Also no_proxy) If both HTTP_PROXY and NO_PROXY are
              set, NO_PROXY will be treated as a comma-separated list of "bypass" domains
              which will not be sent through the proxy. Domains in NO_PROXY may contain
              wildcards, as in "*.mono-project.com" or "build????.local". Not supported on
              Windows, Mac OS, iOS or Android.

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:

              align-small-structs
                     Enables small structs alignment to 4/8 bytes.

              arm-use-fallback-tls
                     When this option is set on ARM, a fallback thread local
                     store will be used instead of the default fast thread local
                     storage primitives.

              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.

              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.

              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.

              debug-domain-unload
                     When this option is set, the runtime will invalidate the
                     domain memory pool instead of destroying it.

              disable_omit_fp
                     Disables a compiler optimization where the frame pointer is
                     omitted from the stack. This optimization can interact
                     badly with debuggers.

              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.

              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.

              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.

              llvm-disable-implicit-null-checks
                     Makes the LLVM backend use explicit NULL checks on variable
                     dereferences instead of depending on operating system
                     support for signals or traps when an invalid memory
                     location is accessed. Unconditionally enabled by explicit-
                     null-checks.

              no-compact-seq-points
                     Unless the option is used, the runtime generates sequence
                     points data that maps native offsets to IL offsets.
                     Sequence point data is used to display IL offset in
                     stacktraces. Stacktraces with IL offsets can be
                     symbolicated using mono-symbolicate tool.

              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.

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

              partial-sharing
                     When this option is set, the runtime can share generated
                     code between generic types effectively reducing the amount
                     of code generated.

              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.

              single-imm-size
                     This guarantees that each time managed code is compiled the
                     same instructions and registers are used, regardless of the
                     size of used values.

              soft-breakpoints
                     This option allows using single-steps and breakpoints in
                     hardware where we cannot do it with signals.

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

              suspend-on-sigsegv
                     Same as suspend-on-native-crash.

              suspend-on-exception
                     This option will suspend the program when an exception
                     occurs.

              suspend-on-unhandled
                     This option will suspend the program when an unhandled
                     exception occurs.

              thread-dump-dir=DIR
                     Use DIR for storage thread dumps created by SIGQUIT.

              weak-memory-model
                     Don't enforce the CLR memory model on platforms with weak
                     memory models. This can introduce random crashes in some
                     rare cases, for multithreaded environments. This can be
                     used for a performance boost on applications that are
                     single threaded.

              verbose-gdb
                     Make gdb output on native crashes more verbose.

       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_LOG_DEST
              Controls where trace log messages are written. If not set then the
              messages go to stdout.  If set, the string either specifies a path
              to a file that will have messages appended to it, or the string
              "syslog" in which case the messages will be written to the system
              log.  Under Windows, this is simulated by writing to a file called
              "mono.log".  MONO_LOG_HEADER Controls whether trace log messages
              not directed to syslog have the id, timestamp, and pid as the
              prefix to the log message. To enable a header this environment
              variable need just be non-null.

       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_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.   This can be a semicolon-separated list of
              method names to match.  If the name is simple, this applies to any
              method with that name, otherwise you can use a mono method
              description (see the section METHOD DESCRIPTIONS).

       MONO_JIT_DUMP_METHOD
              Enables sending of the JITs intermediate representation for a
              specified method to the IdealGraphVisualizer tool.

       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), cert-sync(1), csharp(1), gacutil(1), mcs(1), monodis(1),
       mono-config(5), mono-profilers(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)