3 .\" Copyright 2003 Ximian, Inc.
4 .\" Copyright 2004-2011 Novell, Inc.
5 .\" Copyright 2011-2012 Xamarin Inc
6 .\" Copyright 2013 7digital Media Ltd.
8 .\" Miguel de Icaza (miguel@gnu.org)
12 mono \- Mono's ECMA-CLI native code generator (Just-in-Time and Ahead-of-Time)
15 .B mono [options] file [arguments...]
17 .B mono-sgen [options] file [arguments...]
19 \fImono\fP is a runtime implementation of the ECMA Common Language
20 Infrastructure. This can be used to run ECMA and .NET applications.
22 The runtime loads the specified
29 is an ECMA assembly. They typically have a .exe or .dll extension.
31 These executables can reference additional functionality in the form
32 of assembly references. By default those assembly references are
33 resolved as follows: the \fBmscorlib.dll\fR is resolved from the
34 system profile that is configured by Mono, and other assemblies are
35 loaded from the Global Assembly Cache (GAC).
37 The runtime contains a native code generator that transforms the
38 Common Intermediate Language into native code.
40 The code generator can operate in two modes: Just-in-time compilation
41 (JIT) or Ahead-of-time compilation (AOT). Since code can be
42 dynamically loaded, the runtime environment and the JIT are always
43 present, even if code is compiled ahead of time.
45 The runtime provides a number of configuration options for running
46 applications, for developing and debugging, and for testing and
47 debugging the runtime itself.
49 The \fImono\fP command uses the moving and generational SGen garbage collector
50 while the \fImono-boehm\fP command uses the conservative Boehm
53 On Unix-based systems, Mono provides a mechanism to emulate the
54 Windows-style file access, this includes providing a case insensitive
55 view of the file system, directory separator mapping (from \\ to /) and
56 stripping the drive letters.
58 This functionality is enabled by setting the
60 environment variable to one of
65 See the description for
67 in the environment variables section for more details.
68 .SH METHOD DESCRIPTIONS
69 A number of diagnostic command line options take as argument a method
70 description. A method description is a textual representation that
71 can be used to uniquely identify a method. The syntax is as follows:
73 [namespace]classname:methodname[(arguments)]
76 The values in brackets are optional, like the namespace and the
77 arguments. The arguments themselves are either empty, or a
78 comma-separated list of arguments. Both the
82 can be set to the special value '*' to match any values (Unix shell
83 users should escape the argument to avoid the shell interpreting
86 The arguments, if present should be a comma separated list of types
87 either a full typename, or for built-in types it should use the
88 low-level ILAsm type names for the built-in types,
89 like 'void', 'char', 'bool', 'byte', 'sbyte', 'uint16', 'int16', 'uint',
90 'int', 'ulong', 'long', 'uintptr', 'intptr', 'single', 'double', 'string', 'object'.
92 Pointer types should be the name of the type, followed by a '*',
93 arrays should be the typename followed by '[' one or more commas (to
94 indicate the rank of the array), and ']'.
96 Generic values should use '<', one or more type names, separated by
97 both a comma and a space and '>'.
99 By-reference arguments should include a "&" after the typename.
103 *:ctor(int) // All constructors that take an int as an argument
104 *:Main // Methods named Main in any class
105 *:Main(string[]) // Methods named Main that take a string array in any class
108 The following options are available:
110 \fB--aot\fR, \fB--aot[=options]\fR
111 This option is used to precompile the CIL code in the specified
112 assembly to native code. The generated code is stored in a file with
113 the extension .so. This file will be automatically picked up by the
114 runtime when the assembly is executed.
116 Ahead-of-Time compilation is most useful if you use it in combination
117 with the -O=all,-shared flag which enables all of the optimizations in
118 the code generator to be performed. Some of those optimizations are
119 not practical for Just-in-Time compilation since they might be very
122 Unlike the .NET Framework, Ahead-of-Time compilation will not generate
123 domain independent code: it generates the same code that the
124 Just-in-Time compiler would produce. Since most applications use a
125 single domain, this is fine. If you want to optimize the generated
126 code for use in multi-domain applications, consider using the
129 This pre-compiles the methods, but the original assembly is still
130 required to execute as this one contains the metadata and exception
131 information which is not available on the generated file. When
132 precompiling code, you might want to compile with all optimizations
133 (-O=all). Pre-compiled code is position independent code.
135 Precompilation is just a mechanism to reduce startup time, increase
136 code sharing across multiple mono processes and avoid just-in-time
137 compilation program startup costs. The original assembly must still
138 be present, as the metadata is contained there.
140 AOT code typically can not be moved from one computer to another
141 (CPU-specific optimizations that are detected at runtime) so you
142 should not try to move the pre-generated assemblies or package the
143 pre-generated assemblies for deployment.
145 A few options are available as a parameter to the
147 command line option. The options are separated by commas, and more
148 than one can be specified:
153 Instructs the AOT compiler to output assembly code instead of an
156 .I bind-to-runtime-version
158 If specified, forces the generated AOT files to be bound to the
159 runtime version of the compiling Mono. This will prevent the AOT
160 files from being consumed by a different Mono runtime.
162 .I data-outfile=FILE.dll.aotdata
164 This instructs the AOT code generator to output certain data
165 constructs into a separate file. This can reduce the executable
166 images some five to twenty percent. Developers need to then ship the
167 resulting aotdata as a resource and register a hook to load the data
168 on demand by using the
169 .I mono_install_load_aot_data_hook
174 When this option is specified, icalls (internal calls made from the
175 standard library into the mono runtime code) are invoked directly
176 instead of going through the operating system symbol lookup operation.
177 This requires use of the
183 When this option is specified, P/Invoke methods are invoked directly
184 instead of going through the operating system symbol lookup operation.
185 This requires use of the
190 Instructs the AOT compiler to emit DWARF debugging information. When
191 used together with the nodebug option, only DWARF debugging
192 information is emitted, but not the information that can be used at
197 This creates binaries which can be used with the --full-aot option.
201 This creates binaries which can be used with the --hybrid-aot option.
204 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.
207 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
211 automatically enables the
215 options. This feature is experimental.
217 .I llvmopts=[options]
218 Use this option to add more flags to the built-in set of flags passed to the
219 LLVM optimizer. When you invoke the
223 it displays the current list of flags that are being passed to the
226 .I The list of possible flags that can be passed can be
227 obtained by calling the bundled
229 program that comes with Mono, and calling it like this:
238 Use this option to add more flags to the built-in set of flags passed to the
239 LLVM static compiler (llc). The list of possible flags that can be passed can be
240 obtained by calling the bundled
242 program that comes with Mono, and calling it like this:
249 .I mcpu=[native o generic]
250 cpu=native allows AOT mode to use all instructions current CPU supports, e.g. AVX2, SSE42, etc.
251 Default value is 'generic'.
252 .I mattr=[cpu feature]
253 Allows AOT code generator to use specified CPU features where possible including `System.Runtime.Intrinsics.*'.
254 E.g. `mattr=+avx2,mattr=-lzcnt' unlocks sse1-4.2, avx1-2 and disables lzcnt.
255 It's useful for cross-compilation or when it's not possible to use `-mcpu=native' (which enables
256 all cpu feature current cpu has).
257 .I llvm-outfile=[filename]
258 Gives the path for the temporary LLVM bitcode file created during AOT.
260 Each AOT module will typically contain the code for inflated methods and wrappers that
261 are called by code in that module. In dedup mode, we identify and skip compiling all of those
262 methods. When using this mode with fullaot, dedup-include is required or these methods will
265 .I dedup-include=[filename]
266 In dedup-include mode, we are in the pass of compilation where we compile the methods
267 that we had previously skipped. All of them are emitted into the assembly that is passed
268 as this option. We consolidate the many duplicate skipped copies of the same method into one.
272 Print the architecture the AOT in this copy of Mono targets and quit.
275 Generates all required wrappers, so that it is possible to run --interpreter without
276 any code generation at runtime. This option only makes sense with \fBmscorlib.dll\fR.
279 .I depfile=[filename]
280 Outputs a gcc -M style dependency file.
283 mono_jit_set_aot_mode (MONO_AOT_MODE_INTERP);
288 Additional flags to pass to the C linker (if the current AOT mode calls for invoking it).
290 .I llvm-path=<PREFIX>
291 Same for the llvm tools 'opt' and 'llc'.
294 Instructs the AOT compiler to generate offline sequence points .msym files.
295 The generated .msym files will be stored into a subfolder of <PATH> named as the
299 Use the GNU style target triple <TRIPLE> to determine some code generation options, i.e.
300 --mtriple=armv7-linux-gnueabi will generate code that targets ARMv7. This is currently
301 only supported by the ARM backend. In LLVM mode, this triple is passed on to the LLVM
304 .I nimt-trampolines=[number]
305 When compiling in full aot mode, the IMT trampolines must be precreated
306 in the AOT image. You can add additional method trampolines with this argument.
309 .I ngsharedvt-trampolines=[number]
310 When compiling in full aot mode, the value type generic sharing trampolines must be precreated
311 in the AOT image. You can add additional method trampolines with this argument.
315 Instructs the AOT compiler to not output any debugging information.
318 This prevents the AOT compiler from generating a direct calls to a
319 method. The AOT compiler usually generates direct calls for certain
320 methods that do not require going through the PLT (for example,
321 methods that are known to not require a hook like a static
322 constructor) or call into simple internal calls.
324 .I nrgctx-trampolines=[number]
325 When compiling in full aot mode, the generic sharing trampolines must be precreated
326 in the AOT image. You can add additional method trampolines with this argument.
329 .I nrgctx-fetch-trampolines=[number]
330 When compiling in full aot mode, the generic sharing fetch trampolines must be precreated
331 in the AOT image. You can add additional method trampolines with this argument.
334 .I ntrampolines=[number]
335 When compiling in full aot mode, the method trampolines must be precreated
336 in the AOT image. You can add additional method trampolines with this argument.
339 .I outfile=[filename]
340 Instructs the AOT compiler to save the output to the specified file.
342 .I print-skipped-methods
343 If the AOT compiler cannot compile a method for any reason, enabling this flag
344 will output the skipped methods to the console.
347 Specify a file to use for profile-guided optimization. See the \fBAOT profiler\fR sub-section. To specify multiple files, include the
349 option multiple times.
352 AOT *only* the methods described in the files specified with the
354 option. See the \fBAOT profiler\fR sub-section.
356 .I readonly-value=namespace.typename.fieldname=type/value
357 Override the value of a static readonly field. Usually, during JIT
358 compilation, the static constructor is ran eagerly, so the value of
359 a static readonly field is known at compilation time and the compiler
360 can do a number of optimizations based on it. During AOT, instead, the static
361 constructor can't be ran, so this option can be used to set the value of such
362 a field and enable the same set of optimizations.
363 Type can be any of i1, i2, i4 for integers of the respective sizes (in bytes).
364 Note that signed/unsigned numbers do not matter here, just the storage size.
365 This option can be specified multiple times and it doesn't prevent the static
366 constructor for the type defining the field to execute with the usual rules
367 at runtime (hence possibly computing a different value for the field).
369 .I save-temps,keep-temps
370 Instructs the AOT compiler to keep temporary files.
373 This instructs the compiler to generate sequence point checks that
374 allow Mono's soft debugger to debug applications even on systems where
375 it is not possible to set breakpoints or to single step (certain
376 hardware configurations like the cell phones and video gaming
380 Create an ELF object file (.o) or .s file which can be statically linked into an
381 executable when embedding the mono runtime. When this option is used, the object file
382 needs to be registered with the embedded runtime using the mono_aot_register_module
383 function which takes as its argument the mono_aot_module_<ASSEMBLY NAME>_info global
384 symbol from the object file:
387 extern void *mono_aot_module_hello_info;
389 mono_aot_register_module (mono_aot_module_hello_info);
394 Print various stats collected during AOT compilation.
397 Explicitly specify path to store temporary files created during AOT compilation.
400 This is an experimental option for the AOT compiler to use multiple threads
401 when compiling the methods.
403 .I tool-prefix=<PREFIX>
404 Prepends <PREFIX> to the name of tools ran by the AOT compiler, i.e. 'as'/'ld'. For
405 example, --tool=prefix=arm-linux-gnueabi- will make the AOT compiler run
406 'arm-linux-gnueabi-as' instead of 'as'.
409 Prints additional information about type loading failures.
411 .I write-symbols,no-write-symbols
412 Instructs the AOT compiler to emit (or not emit) debug symbol information.
415 Instructs the AOT compiler tot no call opt when compiling with LLVM.
417 For more information about AOT, see: http://www.mono-project.com/docs/advanced/aot/
420 \fB--aot-path=PATH\fR
421 List of additional directories to search for AOT images.
423 \fB--apply-bindings=FILE\fR
424 Apply the assembly bindings from the specified configuration file when running
425 the AOT compiler. This is useful when compiling an auxiliary assembly that is
426 referenced by a main assembly that provides a configuration file. For example,
427 if app.exe uses lib.dll then in order to make the assembly bindings from
428 app.exe.config available when compiling lib.dll ahead of time, use:
430 mono --apply-bindings=app.exe.config --aot lib.dll
433 \fB--assembly-loader=MODE\fR
434 If mode is \fBstrict\fR, Mono will check that the public key token, culture and version
435 of a candidate assembly matches the requested strong name. If mode is \fBlegacy\fR, as
436 long as the name matches, the candidate will be allowed. \fBstrict\fR is the behavior
437 consistent with .NET Framework but may break some existing mono-based applications.
438 The default is \fBlegacy\fR.
440 \fB--attach=[options]\fR
441 Currently the only option supported by this command line argument is
442 \fBdisable\fR which disables the attach functionality.
444 \fB--config filename\fR
445 Load the specified configuration file instead of the default one(s).
446 The default files are /etc/mono/config and ~/.mono/config or the file
447 specified in the MONO_CONFIG environment variable, if set. See the
448 mono-config(5) man page for details on the format of this file.
450 \fB--debugger-agent=[options]\fR
451 This instructs the Mono runtime to
452 start a debugging agent inside the Mono runtime and connect it to a
453 client user interface will control the Mono process.
454 This option is typically used by IDEs, like the MonoDevelop or Visual Studio IDEs.
456 The configuration is specified using one of more of the following options:
462 Use this option to specify the IP address where your debugger client is
467 Specifies the diagnostics log level for
471 Used to specify the file where the log will be stored, it defaults to
475 Defaults to no, with the default option Mono will actively connect to the
476 host/port configured with the \fBaddress\fR option. If you set it to 'y', it
477 instructs the Mono runtime to start debugging in server mode, where Mono
478 actively waits for the debugger front end to connect to the Mono process.
479 Mono will print out to stdout the IP address and port where it is listening.
482 If set to yes, Mono will call \fBsetpgid(0, 0)\fR on startup, if that function
483 is available on the system. This is useful for ensuring that signals delivered
484 to a process that is executing the debuggee are not propagated to the debuggee,
485 e.g. when Ctrl-C sends \fBSIGINT\fR to the \fBsdb\fR tool.
488 Defaults to yes, with the default option Mono will suspend the vm on startup
489 until it connects successfully to a debugger front end. If you set it to 'n', in
490 conjunction with \fBserver=y\fR, it instructs the Mono runtime to run as normal,
491 while caching metadata to send to the debugger front end on connection..
493 .I transport=transport_name
495 This is used to specify the transport that the debugger will use to
496 communicate. It must be specified and currently requires this to
502 Configures the virtual machine to be better suited for desktop
503 applications. Currently this sets the GC system to avoid expanding
504 the heap as much as possible at the expense of slowing down garbage
508 This flag instructs the Mono runtime to not
509 generate any code at runtime and depend exclusively on the code
510 generated from using mono --aot=full previously. This is useful for
511 platforms that do not permit dynamic code generation, or if you need
512 to run assemblies that have been stripped of IL (for example using
515 Notice that this feature will abort execution at runtime if a codepath
516 in your program, or Mono's class libraries attempts to generate code
517 dynamically. You should test your software upfront and make sure that
518 you do not use any dynamic features.
520 \fB--full-aot-interp\fR
521 Same as --full-aot with fallback to the interpreter.
523 \fB--gc=boehm\fR, \fB--gc=sgen\fR
524 Selects the Garbage Collector engine for Mono to use, Boehm or SGen.
525 Currently this merely ensures that you are running either the
526 \fImono\fR or \fImono-sgen\fR commands. This flag can be set in the
527 \fBMONO_ENV_OPTIONS\fR environment variable to force all of your child
528 processes to use one particular kind of GC with the Mono runtime.
530 \fB--gc-debug=[options]\fR
531 Command line equivalent of the \fBMONO_GC_DEBUG\fR environment variable.
533 \fB--gc-params=[options]\fR
534 Command line equivalent of the \fBMONO_GC_PARAMS\fR environment variable.
536 \fB--arch=32\fR, \fB--arch=64\fR
537 (Mac OS X only): Selects the bitness of the Mono binary used, if
538 available. If the binary used is already for the selected bitness, nothing
539 changes. If not, the execution switches to a binary with the selected
540 bitness suffix installed side by side (for example, '/bin/mono --arch=64'
541 will switch to '/bin/mono64' iff '/bin/mono' is a 32-bit build).
543 \fB--help\fR, \fB-h\fR
544 Displays usage instructions.
547 The Mono runtime will use its interpreter to execute a given assembly.
548 The interpreter is usually slower than the JIT, but it can be useful on
549 platforms where code generation at runtime is not allowed.
552 This flag allows the Mono runtime to run assemblies
553 that have been stripped of IL, for example using mono-cil-strip. For this to
554 work, the assembly must have been AOT compiled with --aot=hybrid.
556 This flag is similar to --full-aot, but it does not disable the JIT. This means
557 you can use dynamic features such as System.Reflection.Emit.
560 If the Mono runtime has been compiled with LLVM support (not available
561 in all configurations), Mono will use the LLVM optimization and code
562 generation engine to JIT or AOT compile.
564 For more information, consult: http://www.mono-project.com/docs/advanced/mono-llvm/
567 This flag allows Mono and LLVM to apply aggressive floating point optimizations.
568 Can break IEEE754 compliance.
571 When using a Mono that has been compiled with LLVM support, it forces
572 Mono to fallback to its JIT engine and not use the LLVM backend.
574 \fB--optimize=MODE\fR, \fB-O=MODE\fR
575 MODE is a comma separated list of optimizations. They also allow
576 optimizations to be turned off by prefixing the optimization name with
579 In general, Mono has been tuned to use the default set of flags,
580 before using these flags for a deployment setting, you might want to
581 actually measure the benefits of using them.
583 The following optimization flags are implemented in the core engine:
585 abcrem Array bound checks removal
586 all Turn on all optimizations
587 aot Usage of Ahead Of Time compiled code
588 branch Branch optimizations
589 cfold Constant folding
590 cmov Conditional moves [arch-dependency]
591 deadce Dead code elimination
592 consprop Constant propagation
593 copyprop Copy propagation
594 fcmov Fast x86 FP compares [arch-dependency]
595 float32 Perform 32-bit float arithmetic using 32-bit operations
596 gshared Enable generic code sharing.
597 inline Inline method calls
598 intrins Intrinsic method implementations
599 linears Linear scan global reg allocation
600 leaf Leaf procedures optimizations
601 loop Loop related optimizations
602 peephole Peephole postpass
603 precomp Precompile all methods before executing Main
604 sched Instruction scheduling
605 shared Emit per-domain code
606 sse2 SSE2 instructions on x86 [arch-dependency]
607 tailc Tail recursion and tail calls
610 For example, to enable all the optimization but dead code
611 elimination and inlining, you can use:
613 -O=all,-deadce,-inline
616 The flags that are flagged with [arch-dependency] indicate that the
617 given option if used in combination with Ahead of Time compilation
618 (--aot flag) would produce pre-compiled code that will depend on the
619 current CPU and might not be safely moved to another computer.
623 The following optimizations are supported
626 Requests that the runtime performn 32-bit floating point operations
627 using only 32-bits. By default the Mono runtime tries to use the
628 highest precision available for floating point operations, but while
629 this might render better results, the code might run slower. This
630 options also affects the code generated by the LLVM backend.
633 Controls whether the runtime should attempt to inline (the default),
634 or not inline methods invocations
637 \fB--response=FILE\fR
638 Provides a response file, this instructs the Mono command to read
639 other command line options from the specified file, as if the
640 options had been specified on the command line. Useful when you have
641 very long command lines.
643 \fB--runtime=VERSION\fR
644 Mono supports different runtime versions. The version used depends on the program
645 that is being run or on its configuration file (named program.exe.config). This option
646 can be used to override such autodetection, by forcing a different runtime version
647 to be used. Note that this should only be used to select a later compatible runtime
648 version than the one the program was compiled against. A typical usage is for
649 running a 1.1 program on a 2.0 version:
651 mono --runtime=v2.0.50727 program.exe
655 Configures the virtual machine to be better suited for server
656 operations (currently, allows a heavier threadpool initialization).
659 Instructs Mono to generate code using MAP_JIT on MacOS. Necessary for
660 bundled applications.
663 Verifies mscorlib and assemblies in the global
664 assembly cache for valid IL, and all user code for IL
667 This is different from \fB--security\fR's verifiable
668 or validil in that these options only check user code and skip
669 mscorlib and assemblies located on the global assembly cache.
671 \fB-V\fR, \fB--version\fR
672 Prints JIT version information (system configuration, release number
673 and branch names if available).
675 \fB--version=number\fR
676 Print version number only.
679 .SH DEVELOPMENT OPTIONS
680 The following options are used to help when developing a JITed application.
682 \fB--debug\fR, \fB--debug=OPTIONS\fR
683 Turns on the debugging mode in the runtime. If an assembly was
684 compiled with debugging information, it will produce line number
685 information for stack traces.
689 The optional OPTIONS argument is a comma separated list of debugging
690 options. These options are turned off by default since they generate
691 much larger and slower code at runtime.
693 The following options are supported:
696 Produces a detailed error when throwing a InvalidCastException. This
697 option needs to be enabled as this generates more verbose code at
701 Disable some JIT optimizations which are usually only disabled when
702 running inside the debugger. This can be helpful if you want to attach
703 to the running process with mdb.
706 Generate and register debugging information with gdb. This is only supported on some
707 platforms, and only when using gdb 7.0 or later.
711 \fB\-\-profile\fR[=\fIprofiler\fR[:\fIprofiler_args\fR]]\fR
712 Loads a profiler module with the given arguments. For more information,
713 see the \fBPROFILING\fR section.
715 This option can be used multiple times; each time will load an additional
718 \fB--trace[=expression]\fR
719 Shows method names as they are invoked. By default all methods are
722 The trace can be customized to include or exclude methods, classes or
723 assemblies. A trace expression is a comma separated list of targets,
724 each target can be prefixed with a minus sign to turn off a particular
725 target. The words `program', `all' and `disabled' have special
726 meaning. `program' refers to the main program being executed, and
727 `all' means all the method calls.
729 The `disabled' option is used to start up with tracing disabled. It
730 can be enabled at a later point in time in the program by sending the
731 SIGUSR2 signal to the runtime.
733 Assemblies are specified by their name, for example, to trace all
734 calls in the System assembly, use:
737 mono --trace=System app.exe
740 Classes are specified with the T: prefix. For example, to trace all
741 calls to the System.String class, use:
744 mono --trace=T:System.String app.exe
747 And individual methods are referenced with the M: prefix, and the
748 standard method notation:
751 mono --trace=M:System.Console:WriteLine app.exe
754 Exceptions can also be traced, it will cause a stack trace to be
755 printed every time an exception of the specified type is thrown.
756 The exception type can be specified with or without the namespace,
757 and to trace all exceptions, specify 'all' as the type name.
760 mono --trace=E:System.Exception app.exe
763 As previously noted, various rules can be specified at once:
766 mono --trace=T:System.String,T:System.Random app.exe
769 You can exclude pieces, the next example traces calls to
770 System.String except for the System.String:Concat method.
773 mono --trace=T:System.String,-M:System.String:Concat
776 You can trace managed to unmanaged transitions using
777 the wrapper qualifier:
780 mono --trace=wrapper app.exe
783 Finally, namespaces can be specified using the N: prefix:
786 mono --trace=N:System.Xml
790 \fB--no-x86-stack-align\fR
791 Don't align stack frames on the x86 architecture. By default, Mono
792 aligns stack frames to 16 bytes on x86, so that local floating point
793 and SIMD variables can be properly aligned. This option turns off the
794 alignment, which usually saves one instruction per call, but might
795 result in significantly lower floating point and SIMD performance.
798 Generate a JIT method map in a /tmp/perf-PID.map file. This file is then
799 used, for example, by the perf tool included in recent Linux kernels.
800 Each line in the file has:
803 HEXADDR HEXSIZE methodname
806 Currently this option is only supported on Linux.
807 .SH JIT MAINTAINER OPTIONS
808 The maintainer options are only used by those developing the runtime
809 itself, and not typically of interest to runtime users or developers.
811 \fB--bisect=optimization:filename\fR
812 This flag is used by the automatic optimization bug bisector. It
813 takes an optimization flag and a filename of a file containing a list
814 of full method names, one per line. When it compiles one of the
815 methods in the file it will use the optimization given, in addition to
816 the optimizations that are otherwise enabled. Note that if the
817 optimization is enabled by default, you should disable it with `-O`,
818 otherwise it will just apply to every method, whether it's in the file
822 Inserts a breakpoint before the method whose name is `method'
823 (namespace.class:methodname). Use `Main' as method name to insert a
824 breakpoint on the application's main method. You can use it also with
825 generics, for example "System.Collections.Generic.Queue`1:Peek"
828 Inserts a breakpoint on exceptions. This allows you to debug your
829 application with a native debugger when an exception is thrown.
832 This compiles a method (namespace.name:methodname), this is used for
833 testing the compiler performance or to examine the output of the code
837 Compiles all the methods in an assembly. This is used to test the
838 compiler performance or to examine the output of the code generator
840 \fB--graph=TYPE METHOD\fR
841 This generates a postscript file with a graph with the details about
842 the specified method (namespace.name:methodname). This requires `dot'
843 and ghostview to be installed (it expects Ghostview to be called
846 The following graphs are available:
848 cfg Control Flow Graph (CFG)
850 code CFG showing code
851 ssa CFG showing code after SSA translation
852 optcode CFG showing code after IR optimizations
855 Some graphs will only be available if certain optimizations are turned
859 Instruct the runtime on the number of times that the method specified
860 by --compile (or all the methods if --compile-all is used) to be
861 compiled. This is used for testing the code generator performance.
863 \fB--stats=[method]\fR
864 Displays information about the work done by the runtime during the
865 execution of an application. If a method (namespace.name:methodname)
866 is specified, it will display that information when the method is
867 first run in addition to the end of program execution.
869 \fB--wapi=hps|semdel\fR
870 Perform maintenance of the process shared data.
872 semdel will delete the global semaphore.
874 hps will list the currently used handles.
876 \fB-v\fR, \fB--verbose\fR
877 Increases the verbosity level, each time it is listed, increases the
878 verbosity level to include more information (including, for example,
879 a disassembly of the native code produced, code selector info etc.).
881 The Mono runtime allows external processes to attach to a running
882 process and load assemblies into the running program. To attach to
883 the process, a special protocol is implemented in the Mono.Management
886 With this support it is possible to load assemblies that have an entry
887 point (they are created with -target:exe or -target:winexe) to be
888 loaded and executed in the Mono process.
890 The code is loaded into the root domain, and it starts execution on
891 the special runtime attach thread. The attached program should
892 create its own threads and return after invocation.
894 This support allows for example debugging applications by having the
895 csharp shell attach to running processes.
897 The Mono runtime includes a profiler API that dynamically loaded
898 profiler modules and embedders can use to collect performance-related
899 data about an application. Profiler modules are loaded by passing the
900 \fB\-\-profile\fR command line argument to the Mono runtime.
902 Mono ships with a few profiler modules, of which the \fBlog\fR profiler
903 is the most feature-rich. It is also the default profiler if the
904 \fIprofiler\fR argument is not given, or if \fBdefault\fR is given.
905 It is possible to write your own profiler modules; see the
906 \fBCustom profilers\fR sub-section.
908 The log profiler can be used to collect a lot of information about
909 a program running in the Mono runtime. This data can be used (both
910 while the process is running and later) to do analyses of the
911 program behavior, determine resource usage, performance issues or
912 even look for particular execution patterns.
914 This is accomplished by logging the events provided by the Mono
915 runtime through the profiler API and periodically writing them to a
916 file which can later be inspected with the \fBmprof\-report\fR(1)
919 More information about how to use the log profiler is available on
920 the \fBmono\-profilers\fR(1) page, under the \fBLOG PROFILER\fR
921 section, as well as the \fBmprof\-report\fR(1) page.
922 .SS Coverage profiler
923 The code coverage profiler can instrument a program to help determine
924 which classes, methods, code paths, etc are actually executed. This
925 is most useful when running a test suite to determine whether the
926 tests actually cover the code they're expected to.
928 More information about how to use the coverage profiler is available
929 on the \fBmono\-profilers\fR(1) page, under the \fBCOVERAGE
932 The AOT profiler can help improve startup performance by logging
933 which generic instantiations are used by a program, which the AOT
934 compiler can then use to compile those instantiations ahead of time
935 so that they won't have to be JIT compiled at startup.
937 More information about how to use the AOT profiler is available on
938 the \fBmono\-profilers\fR(1) page, under the \fBAOT PROFILER\fR
941 Custom profiler modules can be loaded in exactly the same way as the
942 standard modules that ship with Mono. They can also access the same
943 profiler API to gather all kinds of information about the code being
946 For example, to use a third-party profiler called \fBcustom\fR, you
947 would load it like this:
951 mono --profile=custom program.exe
955 You could also pass arguments to it:
959 mono --profile=custom:arg1,arg2=arg3 program.exe
963 In the above example, Mono will load the profiler from the shared
964 library called \fIlibmono\-profiler\-custom.so\fR (name varies based
965 on platform, e.g., \fIlibmono\-profiler\-custom.dylib\fR on OS X).
966 This profiler module must be on your dynamic linker library path
967 (\fBLD_LIBRARY_PATH\fR on most systems, \fBDYLD_LIBRARY_PATH\fR on
970 For a sample of how to write your own custom profiler, look at the
971 \fIsamples/profiler/sample.c\fR file in the Mono source tree.
973 To debug managed applications, you can use the
975 command, a command line debugger.
977 It is possible to obtain a stack trace of all the active threads in
978 Mono by sending the QUIT signal to Mono, you can do this from the
979 command line, like this:
985 Where pid is the Process ID of the Mono process you want to examine.
986 The process will continue running afterwards, but its state is not
990 this is a last-resort mechanism for debugging applications and should
991 not be used to monitor or probe a production application. The
992 integrity of the runtime after sending this signal is not guaranteed
993 and the application might crash or terminate at any given point
996 The \fB--debug=casts\fR option can be used to get more detailed
997 information for Invalid Cast operations, it will provide information
998 about the types involved.
1000 You can use the MONO_LOG_LEVEL and MONO_LOG_MASK environment variables
1001 to get verbose debugging output about the execution of your
1002 application within Mono.
1006 environment variable if set, the logging level is changed to the set
1007 value. Possible values are "error", "critical", "warning", "message",
1008 "info", "debug". The default value is "error". Messages with a logging
1009 level greater then or equal to the log level will be printed to
1012 Use "info" to track the dynamic loading of assemblies.
1017 environment variable to limit the extent of the messages you get:
1018 If set, the log mask is changed to the set value. Possible values are
1019 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1020 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1021 "security" (e.g. Moonlight CoreCLR support), "threadpool" (thread pool generic),
1022 "io-selector" (async socket operations), "io-layer" (I/O layer - processes, files,
1023 sockets, events, semaphores, mutexes and handles), "io-layer-process",
1024 "io-layer-file", "io-layer-socket", "io-layer-event", "io-layer-semaphore",
1025 "io-layer-mutex", "io-layer-handle" and "all".
1026 The default value is "all". Changing the mask value allows you to display only
1027 messages for a certain component. You can use multiple masks by comma
1028 separating them. For example to see config file messages and assembly loader
1029 messages set you mask to "asm,cfg".
1031 The following is a common use to track down problems with P/Invoke:
1034 $ MONO_LOG_LEVEL="debug" MONO_LOG_MASK="dll" mono glue.exe
1038 .SH DEBUGGING WITH LLDB
1039 If you are using LLDB, you can use the
1041 script to print some internal data structures with it. To use this,
1046 command script import $PREFIX/lib/mono/lldb/mono.py
1049 Where $PREFIX is the prefix value that you used when you configured
1050 Mono (typically /usr).
1052 Once this is done, then you can inspect some Mono Runtime data structures,
1057 (MonoMethod *) $0 = 0x05026ac0 [mscorlib]System.OutOfMemoryException:.ctor()
1060 Mono's XML serialization engine by default will use a reflection-based
1061 approach to serialize which might be slow for continuous processing
1062 (web service applications). The serialization engine will determine
1063 when a class must use a hand-tuned serializer based on a few
1064 parameters and if needed it will produce a customized C# serializer
1065 for your types at runtime. This customized serializer then gets
1066 dynamically loaded into your application.
1068 You can control this with the MONO_XMLSERIALIZER_THS environment
1071 The possible values are
1073 to disable the use of a C# customized
1074 serializer, or an integer that is the minimum number of uses before
1075 the runtime will produce a custom serializer (0 will produce a
1076 custom serializer on the first access, 50 will produce a serializer on
1077 the 50th use). Mono will fallback to an interpreted serializer if the
1078 serializer generation somehow fails. This behavior can be disabled
1079 by setting the option
1081 (for example: MONO_XMLSERIALIZER_THS=0,nofallback).
1082 .SH ENVIRONMENT VARIABLES
1085 Turns off the garbage collection in Mono. This should be only used
1086 for debugging purposes
1089 (Also \fBhttp_proxy\fR) If set, web requests using the Mono
1090 Class Library will be automatically proxied through the given URL.
1091 Not supported on Windows, Mac OS, iOS or Android. See also \fBNO_PROXY\fR.
1094 When Mono is compiled with LLVM support, this instructs the runtime to
1095 stop using LLVM after the specified number of methods are JITed.
1096 This is a tool used in diagnostics to help isolate problems in the
1097 code generation backend. For example \fBLLVM_COUNT=10\fR would only
1098 compile 10 methods with LLVM and then switch to the Mono JIT engine.
1099 \fBLLVM_COUNT=0\fR would disable the LLVM engine altogether.
1101 \fBMONO_ASPNET_INHIBIT_SETTINGSMAP\fR
1102 Mono contains a feature which allows modifying settings in the .config files shipped
1103 with Mono by using config section mappers. The mappers and the mapping rules are
1104 defined in the $prefix/etc/mono/2.0/settings.map file and, optionally, in the
1105 settings.map file found in the top-level directory of your ASP.NET application.
1106 Both files are read by System.Web on application startup, if they are found at the
1107 above locations. If you don't want the mapping to be performed you can set this
1108 variable in your environment before starting the application and no action will
1111 \fBMONO_ASPNET_WEBCONFIG_CACHESIZE\fR
1112 Mono has a cache of ConfigSection objects for speeding up WebConfigurationManager
1113 queries. Its default size is 100 items, and when more items are needed, cache
1114 evictions start happening. If evictions are too frequent this could impose
1115 unnecessary overhead, which could be avoided by using this environment variable
1116 to set up a higher cache size (or to lower memory requirements by decreasing it).
1118 \fBMONO_CAIRO_DEBUG_DISPOSE\fR
1119 If set, causes Mono.Cairo to collect stack traces when objects are allocated,
1120 so that the finalization/Dispose warnings include information about the
1124 If set, this variable overrides the default system configuration directory
1125 ($PREFIX/etc). It's used to locate machine.config file.
1128 Sets the style of COM interop. If the value of this variable is "MS"
1129 Mono will use string marhsalling routines from the liboleaut32 for the
1130 BSTR type library, any other values will use the mono-builtin BSTR
1134 If set, this variable overrides the default runtime configuration file
1135 ($PREFIX/etc/mono/config). The --config command line options overrides the
1136 environment variable.
1139 Override the automatic cpu detection mechanism. Currently used only on arm.
1140 The format of the value is as follows:
1146 where V is the architecture number 4, 5, 6, 7 and the options can be currently be
1147 "thumb" or "thumb2". Example:
1150 MONO_CPU_ARCH="armv4 thumb" mono ...
1154 \fBMONO_ARM_FORCE_SOFT_FLOAT\fR
1155 When Mono is built with a soft float fallback on ARM and this variable is set to
1156 "1", Mono will always emit soft float code, even if a VFP unit is
1159 \fBMONO_DARWIN_USE_KQUEUE_FSW\fR
1160 Fall back on the kqueue FileSystemWatcher implementation in Darwin. The default is the FSEvent implementation.
1162 \fBMONO_DARWIN_WATCHER_MAXFDS\fR
1163 This is a debugging aid used to force limits on the kqueue FileSystemWatcher
1164 implementation in Darwin. There is no limit by default.
1166 \fBMONO_DISABLE_MANAGED_COLLATION\fR
1167 If this environment variable is `yes', the runtime uses unmanaged
1168 collation (which actually means no culture-sensitive collation). It
1169 internally disables managed collation functionality invoked via the
1170 members of System.Globalization.CompareInfo class. Collation is
1173 \fBMONO_DISABLE_SHARED_AREA\fR
1174 Unix only: If set, disable usage of shared memory for exposing
1175 performance counters. This means it will not be possible to both
1176 externally read performance counters from this processes or read
1177 those of external processes.
1180 When set, enables the use of a fully managed DNS resolver instead of the
1181 regular libc functions. This resolver performs much better when multiple
1182 queries are run in parallel.
1184 Note that /etc/nsswitch.conf will be ignored.
1186 \fBMONO_EGD_SOCKET\fR
1187 For platforms that do not otherwise have a way of obtaining random bytes
1188 this can be set to the name of a file system socket on which an egd or
1189 prngd daemon is listening.
1191 \fBMONO_ENABLE_AIO\fR
1192 If set, tells mono to attempt using native asynchronous I/O services. If not
1193 set, a default select/poll implementation is used. Currently epoll and kqueue
1196 \fBMONO_THREADS_SUSPEND\fR Selects a mechanism that Mono will use to suspend
1197 threads. May be set to "preemptive", "coop", or "hybrid". Threads may need to
1198 be suspended by the debugger, or using some .NET threading APIs, and most
1199 commonly when the SGen garbage collector needs to stop all threads during a
1200 critical phase of garbage collection. Preemptive mode is the mode that Mono
1201 has used historically, going back to the Boehm days, where the garbage
1202 collector would run at any point and suspend execution of all threads as
1203 required to perform a garbage collection. The cooperative mode on the other
1204 hand requires the cooperation of all threads to stop at a safe point. This
1205 makes for an easier to debug garbage collector and it improves the stability of
1206 the runtime because threads are not suspended when accessing critical
1207 resources. In scenarios where Mono is embedded in another application,
1208 cooperative suspend requires the embedder code to follow coding guidelines in
1209 order to cooperate with the garbage collector. Cooperative suspend in embedded
1210 Mono is currently experimental. Hybrid mode is a combination of the two that
1211 retains better compatability with scenarios where Mono is embedded in another
1212 application: threads that are running managed code or code that comprises the
1213 Mono runtime will be cooperatively suspended, while threads running embedder
1214 code will be preemptively suspended. Hybrid suspend is the default on some
1217 Alternatively, coop and hybrid mode can be enabled at compile time by using the
1218 --enable-cooperative-suspend or --enable-hybrid-suspend flags, respectively,
1219 when calling configure. The \fBMONO_THREADS_SUSPEND\fR environment variable
1220 takes priority over the compiled default.
1222 \fBMONO_ENABLE_COOP_SUSPEND\fR
1223 This environment variable is obsolete, but retained for backward compatibility.
1224 Use \fBMONO_THREADS_SUSPEND\fR set to "coop" instead. Note that if configure flags
1225 were provided to enable cooperative or hybrid suspend, this variable is ignored.
1227 \fBMONO_ENV_OPTIONS\fR
1228 This environment variable allows you to pass command line arguments to
1229 a Mono process through the environment. This is useful for example
1230 to force all of your Mono processes to use LLVM or SGEN without having
1231 to modify any launch scripts.
1233 \fBMONO_SDB_ENV_OPTIONS\fR
1234 Used to pass extra options to the debugger agent in the runtime, as they were passed
1235 using --debugger-agent=.
1237 \fBMONO_EVENTLOG_TYPE\fR
1238 Sets the type of event log provider to use (for System.Diagnostics.EventLog).
1240 Possible values are:
1245 Persists event logs and entries to the local file system.
1247 The directory in which to persist the event logs, event sources and entries
1248 can be specified as part of the value.
1250 If the path is not explicitly set, it defaults to "/var/lib/mono/eventlog"
1251 on unix and "%APPDATA%\mono\eventlog" on Windows.
1256 Uses the native win32 API to write events and registers event logs and
1257 event sources in the registry. This is only available on Windows.
1259 On Unix, the directory permission for individual event log and event source
1260 directories is set to 777 (with +t bit) allowing everyone to read and write
1261 event log entries while only allowing entries to be deleted by the user(s)
1266 Silently discards any events.
1269 The default is "null" on Unix (and versions of Windows before NT), and
1270 "win32" on Windows NT (and higher).
1273 \fBMONO_EXTERNAL_ENCODINGS\fR
1274 If set, contains a colon-separated list of text encodings to try when
1275 turning externally-generated text (e.g. command-line arguments or
1276 filenames) into Unicode. The encoding names come from the list
1277 provided by iconv, and the special case "default_locale" which refers
1278 to the current locale's default encoding.
1280 When reading externally-generated text strings UTF-8 is tried first,
1281 and then this list is tried in order with the first successful
1282 conversion ending the search. When writing external text (e.g. new
1283 filenames or arguments to new processes) the first item in this list
1284 is used, or UTF-8 if the environment variable is not set.
1286 The problem with using MONO_EXTERNAL_ENCODINGS to process your
1287 files is that it results in a problem: although its possible to get
1288 the right file name it is not necessarily possible to open the file.
1289 In general if you have problems with encodings in your filenames you
1290 should use the "convmv" program.
1292 \fBMONO_GC_PARAMS\fR
1293 When using Mono with the SGen garbage collector this variable controls
1294 several parameters of the collector. The variable's value is a comma
1295 separated list of words.
1299 \fBmax-heap-size=\fIsize\fR
1300 Sets the maximum size of the heap. The size is specified in bytes and must
1301 be a power of two. The suffixes `k', `m' and `g' can be used to
1302 specify kilo-, mega- and gigabytes, respectively. The limit is the sum
1303 of the nursery, major heap and large object heap. Once the limit is reached
1304 the application will receive OutOfMemoryExceptions when trying to allocate.
1305 Not the full extent of memory set in max-heap-size could be available to
1306 satisfy a single allocation due to internal fragmentation. By default heap
1307 limits is disabled and the GC will try to use all available memory.
1309 \fBnursery-size=\fIsize\fR
1310 Sets the size of the nursery. The size is specified in bytes and must
1311 be a power of two. The suffixes `k', `m' and `g' can be used to
1312 specify kilo-, mega- and gigabytes, respectively. The nursery is the
1313 first generation (of two). A larger nursery will usually speed up the
1314 program but will obviously use more memory. The default nursery size
1317 \fBmajor=\fIcollector\fR
1318 Specifies which major collector to use.
1319 Options are `marksweep' for the Mark&Sweep collector, `marksweep-conc'
1320 for concurrent Mark&Sweep and `marksweep-conc-par' for parallel and
1321 concurrent Mark&Sweep. The concurrent Mark&Sweep collector is the default.
1323 \fBmode=balanced|throughput|pause\fR[:\fImax-pause\fR]
1324 Specifies what should be the garbage collector's target. The `throughput'
1325 mode aims to reduce time spent in the garbage collector and improve
1326 application speed, the `pause' mode aims to keep pause times to a minimum
1327 and it receives the argument \fImax-pause\fR which specifies the maximum
1328 pause time in milliseconds that is acceptable and the `balanced' mode
1329 which is a general purpose optimal mode.
1331 \fBsoft-heap-limit=\fIsize\fR
1332 Once the heap size gets larger than this size, ignore what the default
1333 major collection trigger metric says and only allow four nursery size's
1334 of major heap growth between major collections.
1336 \fBevacuation-threshold=\fIthreshold\fR
1337 Sets the evacuation threshold in percent. This option is only available
1338 on the Mark&Sweep major collectors. The value must be an
1339 integer in the range 0 to 100. The default is 66. If the sweep phase of
1340 the collection finds that the occupancy of a specific heap block type is
1341 less than this percentage, it will do a copying collection for that block
1342 type in the next major collection, thereby restoring occupancy to close
1343 to 100 percent. A value of 0 turns evacuation off.
1345 \fB(no-)lazy-sweep\fR
1346 Enables or disables lazy sweep for the Mark&Sweep collector. If
1347 enabled, the sweeping of individual major heap blocks is done
1348 piecemeal whenever the need arises, typically during nursery
1349 collections. Lazy sweeping is enabled by default.
1351 \fB(no-)concurrent-sweep\fR
1352 Enables or disables concurrent sweep for the Mark&Sweep collector. If
1353 enabled, the iteration of all major blocks to determine which ones can
1354 be freed and which ones have to be kept and swept, is done
1355 concurrently with the running program. Concurrent sweeping is enabled
1358 \fBstack-mark=\fImark-mode\fR
1359 Specifies how application threads should be scanned. Options are
1360 `precise` and `conservative`. Precise marking allow the collector
1361 to know what values on stack are references and what are not.
1362 Conservative marking threats all values as potentially references
1363 and leave them untouched. Precise marking reduces floating garbage
1364 and can speed up nursery collection and allocation rate, it has
1365 the downside of requiring a significant extra memory per compiled
1366 method. The right option, unfortunately, requires experimentation.
1368 \fBsave-target-ratio=\fIratio\fR
1369 Specifies the target save ratio for the major collector. The collector
1370 lets a given amount of memory to be promoted from the nursery due to
1371 minor collections before it triggers a major collection. This amount
1372 is based on how much memory it expects to free. It is represented as
1373 a ratio of the size of the heap after a major collection.
1374 Valid values are between 0.1 and 2.0. The default is 0.5.
1375 Smaller values will keep the major heap size smaller but will trigger
1376 more major collections. Likewise, bigger values will use more memory
1377 and result in less frequent major collections.
1378 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1380 \fBdefault-allowance-ratio=\fIratio\fR
1381 Specifies the default allocation allowance when the calculated size
1382 is too small. The allocation allowance is how much memory the collector
1383 let be promoted before triggered a major collection.
1384 It is a ratio of the nursery size.
1385 Valid values are between 1.0 and 10.0. The default is 4.0.
1386 Smaller values lead to smaller heaps and more frequent major collections.
1387 Likewise, bigger values will allow the heap to grow faster but use
1388 more memory when it reaches a stable size.
1389 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1391 \fBminor=\fIminor-collector\fR
1392 Specifies which minor collector to use. Options are `simple' which
1393 promotes all objects from the nursery directly to the old generation,
1394 `simple-par' which has same promotion behavior as `simple' but using
1395 multiple workers and `split' which lets objects stay longer on the nursery
1398 \fBalloc-ratio=\fIratio\fR
1399 Specifies the ratio of memory from the nursery to be use by the alloc space.
1400 This only can only be used with the split minor collector.
1401 Valid values are integers between 1 and 100. Default is 60.
1403 \fBpromotion-age=\fIage\fR
1404 Specifies the required age of an object must reach inside the nursery before
1405 been promoted to the old generation. This only can only be used with the
1406 split minor collector.
1407 Valid values are integers between 1 and 14. Default is 2.
1409 \fB(no-)cementing\fR
1410 Enables or disables cementing. This can dramatically shorten nursery
1411 collection times on some benchmarks where pinned objects are referred
1412 to from the major heap.
1414 \fBallow-synchronous-major\fR
1415 This forbids the major collector from performing synchronous major collections.
1416 The major collector might want to do a synchronous collection due to excessive
1417 fragmentation. Disabling this might trigger OutOfMemory error in situations that
1418 would otherwise not happen.
1423 When using Mono with the SGen garbage collector this environment
1424 variable can be used to turn on various debugging features of the
1425 collector. The value of this variable is a comma separated list of
1426 words. Do not use these options in production.
1431 Sets the debug level to the specified number.
1433 \fBprint-allowance\fR
1434 After each major collection prints memory consumption for before and
1435 after the collection and the allowance for the minor collector, i.e. how
1436 much the heap is allowed to grow from minor collections before the next
1437 major collection is triggered.
1440 Gathers statistics on the classes whose objects are pinned in the
1441 nursery and for which global remset entries are added. Prints those
1442 statistics when shutting down.
1444 \fBcollect-before-allocs\fR
1446 \fBcheck-remset-consistency\fR
1447 This performs a remset consistency check at various opportunities, and
1448 also clears the nursery at collection time, instead of the default,
1449 when buffers are allocated (clear-at-gc). The consistency check
1450 ensures that there are no major to minor references that are not on
1451 the remembered sets.
1453 \fBmod-union-consistency-check\fR
1454 Checks that the mod-union cardtable is consistent before each
1455 finishing major collection pause. This check is only applicable to
1456 concurrent major collectors.
1458 \fBcheck-mark-bits\fR
1459 Checks that mark bits in the major heap are consistent at the end of
1460 each major collection. Consistent mark bits mean that if an object is
1461 marked, all objects that it had references to must also be marked.
1463 \fBcheck-nursery-untag\fR
1464 After garbage collections, check whether all vtable pointers are no
1467 \fBxdomain-checks\fR
1468 Performs a check to make sure that no references are left to an
1471 \fBclear-at-tlab-creation\fR
1472 Clears the nursery incrementally when the thread local allocation
1473 buffers (TLAB) are created. The default setting clears the whole
1476 \fBdebug-clear-at-tlab-creation\fR
1477 Clears the nursery incrementally when the thread local allocation
1478 buffers (TLAB) are created, but at GC time fills it with the byte
1479 `0xff`, which should result in a crash more quickly if
1480 `clear-at-tlab-creation` doesn't work properly.
1483 This clears the nursery at GC time instead of doing it when the thread
1484 local allocation buffer (TLAB) is created. The default is to clear
1485 the nursery at TLAB creation time.
1488 Don't do minor collections. If the nursery is full, a major collection
1489 is triggered instead, unless it, too, is disabled.
1492 Don't do major collections.
1494 \fBconservative-stack-mark\fR
1495 Forces the GC to scan the stack conservatively, even if precise
1496 scanning is available.
1498 \fBno-managed-allocator\fR
1499 Disables the managed allocator.
1501 \fBcheck-scan-starts\fR
1502 If set, does a plausibility check on the scan_starts before and after each collection
1504 \fBverify-nursery-at-minor-gc\fR
1505 If set, does a complete object walk of the nursery at the start of each minor collection.
1507 \fBdump-nursery-at-minor-gc\fR
1508 If set, dumps the contents of the nursery at the start of each minor collection. Requires
1509 verify-nursery-at-minor-gc to be set.
1511 \fBheap-dump=\fIfile\fR
1512 Dumps the heap contents to the specified file. To visualize the
1513 information, use the mono-heapviz tool.
1515 \fBbinary-protocol=\fIfile\fR
1516 Outputs the debugging output to the specified file. For this to
1517 work, Mono needs to be compiled with the BINARY_PROTOCOL define on
1518 sgen-gc.c. You can then use this command to explore the output
1520 sgen-grep-binprot 0x1234 0x5678 < file
1523 \fBnursery-canaries\fR
1524 If set, objects allocated in the nursery are suffixed with a canary (guard)
1525 word, which is checked on each minor collection. Can be used to detect/debug
1526 heap corruption issues.
1529 \fBdo-not-finalize(=\fIclasses\fB)\fR
1530 If enabled, finalizers will not be run. Everything else will be
1531 unaffected: finalizable objects will still be put into the
1532 finalization queue where they survive until they're scheduled to
1533 finalize. Once they're not in the queue anymore they will be
1534 collected regularly. If a list of comma-separated class names is
1535 given, only objects from those classes will not be finalized.
1538 \fBlog-finalizers\fR
1539 Log verbosely around the finalization process to aid debugging.
1543 \fBMONO_GAC_PREFIX\fR
1544 Provides a prefix the runtime uses to look for Global Assembly Caches.
1545 Directories are separated by the platform path separator (colons on
1546 unix). MONO_GAC_PREFIX should point to the top directory of a prefixed
1547 install. Or to the directory provided in the gacutil /gacdir command. Example:
1548 .B /home/username/.mono:/usr/local/mono/
1551 (deprecated) Enabled some filename rewriting support to assist badly-written
1552 applications that hard-code Windows paths. It no longer works as of Mono 6.0.
1555 When Mono is using the LLVM code generation backend you can use this
1556 environment variable to pass code generation options to the LLVM
1559 \fBMONO_MANAGED_WATCHER\fR
1560 If set to "disabled", System.IO.FileSystemWatcher will use a file watcher
1561 implementation which silently ignores all the watching requests.
1562 If set to any other value, System.IO.FileSystemWatcher will use the default
1563 managed implementation (slow). If unset, mono will try to use inotify, FAM,
1564 Gamin, kevent under Unix systems and native API calls on Windows, falling
1565 back to the managed implementation on error.
1567 \fBMONO_MESSAGING_PROVIDER\fR
1568 Mono supports a plugin model for its implementation of System.Messaging making
1569 it possible to support a variety of messaging implementations (e.g. AMQP, ActiveMQ).
1570 To specify which messaging implementation is to be used the evironement variable
1571 needs to be set to the full class name for the provider. E.g. to use the RabbitMQ based
1572 AMQP implementation the variable should be set to:
1575 Mono.Messaging.RabbitMQ.RabbitMQMessagingProvider,Mono.Messaging.RabbitMQ
1578 If set causes the mono process to be bound to a single processor. This may be
1579 useful when debugging or working around race conditions.
1582 Disable inlining of thread local accesses. Try setting this if you get a segfault
1583 early on in the execution of mono.
1586 Provides a search path to the runtime where to look for library
1587 files. This is a tool convenient for debugging applications, but
1588 should not be used by deployed applications as it breaks the assembly
1589 loader in subtle ways.
1591 Directories are separated by the platform path separator (colons on unix). Example:
1592 .B /home/username/lib:/usr/local/mono/lib
1594 Relative paths are resolved based on the launch-time current directory.
1596 Alternative solutions to MONO_PATH include: installing libraries into
1597 the Global Assembly Cache (see gacutil(1)) or having the dependent
1598 libraries side-by-side with the main executable.
1600 For a complete description of recommended practices for application
1602 http://www.mono-project.com/docs/getting-started/application-deployment/
1604 \fBMONO_SHARED_DIR\fR
1605 If set its the directory where the ".wapi" handle state is stored.
1606 This is the directory where the Windows I/O Emulation layer stores its
1607 shared state data (files, events, mutexes, pipes). By default Mono
1608 will store the ".wapi" directory in the users's home directory.
1610 \fBMONO_SHARED_HOSTNAME\fR
1611 Uses the string value of this variable as a replacement for the host name when
1612 creating file names in the ".wapi" directory. This helps if the host name of
1613 your machine is likely to be changed when a mono application is running or if
1614 you have a .wapi directory shared among several different computers.
1616 Mono typically uses the hostname to create the files that are used to
1617 share state across multiple Mono processes. This is done to support
1618 home directories that might be shared over the network.
1620 \fBMONO_STRICT_IO_EMULATION\fR
1621 If set, extra checks are made during IO operations. Currently, this
1622 includes only advisory locks around file writes.
1624 \fBMONO_TLS_PROVIDER\fR
1625 This environment variable controls which TLS/SSL provider Mono will
1626 use. The options are usually determined by the operating system where
1627 Mono was compiled and the configuration options that were used for
1633 Uses the default TLS stack that the Mono runtime was configured with.
1634 Usually this is configured to use Apple's SSL stack on Apple
1635 platforms, and Boring SSL on other platforms.
1638 Forces the use of the Apple SSL stack, only works on Apple platforms.
1641 Forces the use of the BoringSSL stack. See
1642 https://opensource.google.com/projects/boringssl for more information
1646 This is the old Mono stack, which only supports SSL and TLS up to
1647 version 1.0. It is deprecated and will be removed in the future.
1650 \fBMONO_TLS_SESSION_CACHE_TIMEOUT\fR
1651 The time, in seconds, that the SSL/TLS session cache will keep it's entry to
1652 avoid a new negotiation between the client and a server. Negotiation are very
1653 CPU intensive so an application-specific custom value may prove useful for
1654 small embedded systems.
1656 The default is 180 seconds.
1658 \fBMONO_THREADS_PER_CPU\fR
1659 The minimum number of threads in the general threadpool will be
1660 MONO_THREADS_PER_CPU * number of CPUs. The default value for this
1663 \fBMONO_XMLSERIALIZER_THS\fR
1664 Controls the threshold for the XmlSerializer to produce a custom
1665 serializer for a given class instead of using the Reflection-based
1666 interpreter. The possible values are `no' to disable the use of a
1667 custom serializer or a number to indicate when the XmlSerializer
1668 should start serializing. The default value is 50, which means that
1669 the a custom serializer will be produced on the 50th use.
1671 \fBMONO_X509_REVOCATION_MODE\fR
1672 Sets the revocation mode used when validating a X509 certificate chain (https,
1673 ftps, smtps...). The default is 'nocheck', which performs no revocation check
1674 at all. The other possible values are 'offline', which performs CRL check (not
1675 implemented yet) and 'online' which uses OCSP and CRL to verify the revocation
1676 status (not implemented yet).
1679 (Also \fBno_proxy\fR) If both \fBHTTP_PROXY\fR and \fBNO_PROXY\fR are
1680 set, \fBNO_PROXY\fR will be treated as a comma-separated list of "bypass" domains
1681 which will not be sent through the proxy. Domains in \fBNO_PROXY\fR may contain
1682 wildcards, as in "*.mono-project.com" or "build????.local". Not supported on
1683 Windows, Mac OS, iOS or Android.
1684 .SH ENVIRONMENT VARIABLES FOR DEBUGGING
1686 \fBMONO_ASPNET_NODELETE\fR
1687 If set to any value, temporary source files generated by ASP.NET support
1688 classes will not be removed. They will be kept in the user's temporary
1692 If set, enables some features of the runtime useful for debugging.
1693 This variable should contain a comma separated list of debugging options.
1694 Currently, the following options are supported:
1698 \fBalign-small-structs\fR
1699 Enables small structs alignment to 4/8 bytes.
1701 \fBarm-use-fallback-tls\fR
1702 When this option is set on ARM, a fallback thread local store will be used instead
1703 of the default fast thread local storage primitives.
1705 \fBbreak-on-unverified\fR
1706 If this variable is set, when the Mono VM runs into a verification
1707 problem, instead of throwing an exception it will break into the
1708 debugger. This is useful when debugging verifier problems
1711 This option can be used to get more detailed information from
1712 InvalidCast exceptions, it will provide information about the types
1715 \fBcheck-pinvoke-callconv\fR
1716 This option causes the runtime to check for calling convention
1717 mismatches when using pinvoke, i.e. mixing cdecl/stdcall. It only
1718 works on windows. If a mismatch is detected, an
1719 ExecutionEngineException is thrown.
1721 \fBcollect-pagefault-stats\fR
1722 Collects information about pagefaults. This is used internally to
1723 track the number of page faults produced to load metadata. To display
1724 this information you must use this option with "--stats" command line
1727 \fBdebug-domain-unload\fR
1728 When this option is set, the runtime will invalidate the domain memory
1729 pool instead of destroying it.
1731 \fBdisable_omit_fp\fR
1732 Disables a compiler optimization where the frame pointer is omitted
1733 from the stack. This optimization can interact badly with debuggers.
1735 \fBdont-free-domains\fR
1736 This is an Optimization for multi-AppDomain applications (most
1737 commonly ASP.NET applications). Due to internal limitations Mono,
1738 Mono by default does not use typed allocations on multi-appDomain
1739 applications as they could leak memory when a domain is unloaded.
1741 Although this is a fine default, for applications that use more than
1742 on AppDomain heavily (for example, ASP.NET applications) it is worth
1743 trading off the small leaks for the increased performance
1744 (additionally, since ASP.NET applications are not likely going to
1745 unload the application domains on production systems, it is worth
1746 using this feature).
1748 \fBdyn-runtime-invoke\fR
1749 Instructs the runtime to try to use a generic runtime-invoke wrapper
1750 instead of creating one invoke wrapper.
1752 \fBexplicit-null-checks\fR
1753 Makes the JIT generate an explicit NULL check on variable dereferences
1754 instead of depending on the operating system to raise a SIGSEGV or
1755 another form of trap event when an invalid memory location is
1759 Equivalent to setting the \fBMONO_XDEBUG\fR variable, this emits
1760 symbols into a shared library as the code is JITed that can be loaded
1761 into GDB to inspect symbols.
1763 \fBgen-seq-points\fR
1764 Automatically generates sequence points where the
1765 IL stack is empty. These are places where the debugger can set a
1768 \fBllvm-disable-implicit-null-checks\fR
1769 Makes the LLVM backend use explicit NULL checks on variable dereferences
1770 instead of depending on operating system support for signals or traps when
1771 an invalid memory location is accessed. Unconditionally enabled by
1772 explicit-null-checks.
1774 \fBno-compact-seq-points\fR
1775 Unless the option is used, the runtime generates sequence points data that
1776 maps native offsets to IL offsets. Sequence point data is used to
1777 display IL offset in stacktraces. Stacktraces with IL offsets can be
1778 symbolicated using mono-symbolicate tool.
1781 Captures the interrupt signal (Control-C) and displays a stack trace
1782 when pressed. Useful to find out where the program is executing at a
1783 given point. This only displays the stack trace of a single thread.
1786 Instructs the runtime to initialize the stack with
1787 some known values (0x2a on x86-64) at the start of a method to assist
1788 in debuggin the JIT engine.
1790 \fBkeep-delegates\fR
1791 This option will leak delegate trampolines that are no longer
1792 referenced as to present the user with more information about a
1793 delegate misuse. Basically a delegate instance might be created,
1794 passed to unmanaged code, and no references kept in managed code,
1795 which will garbage collect the code. With this option it is possible
1796 to track down the source of the problems.
1798 \fBno-gdb-backtrace\fR
1799 This option will disable the GDB backtrace emitted by the runtime
1800 after a SIGSEGV or SIGABRT in unmanaged code.
1802 \fBpartial-sharing\fR
1803 When this option is set, the runtime can share generated code between
1804 generic types effectively reducing the amount of code generated.
1806 \fBreverse-pinvoke-exceptions
1807 This option will cause mono to abort with a descriptive message when
1808 during stack unwinding after an exception it reaches a native stack
1809 frame. This happens when a managed delegate is passed to native code,
1810 and the managed delegate throws an exception. Mono will normally try
1811 to unwind the stack to the first (managed) exception handler, and it
1812 will skip any native stack frames in the process. This leads to
1813 undefined behaviour (since mono doesn't know how to process native
1814 frames), leaks, and possibly crashes too.
1816 \fBsingle-imm-size\fR
1817 This guarantees that each time managed code is compiled the same
1818 instructions and registers are used, regardless of the size of used
1821 \fBsoft-breakpoints\fR
1822 This option allows using single-steps and breakpoints in hardware
1823 where we cannot do it with signals.
1825 \fBsuspend-on-native-crash\fR
1826 This option will suspend the program when a native crash occurs (SIGSEGV, SIGILL, ...).
1827 This is useful for debugging crashes which do not happen under gdb,
1828 since a live process contains more information than a core file.
1830 \fBsuspend-on-sigsegv\fR
1831 Same as \fBsuspend-on-native-crash\fR.
1833 \fBsuspend-on-exception\fR
1834 This option will suspend the program when an exception occurs.
1836 \fBsuspend-on-unhandled\fR
1837 This option will suspend the program when an unhandled exception occurs.
1839 \fBthread-dump-dir=DIR\fR
1840 Use DIR for storage thread dumps created by SIGQUIT.
1842 \fBweak-memory-model\fR
1843 Don't enforce the CLR memory model on platforms with weak memory models. This can introduce
1844 random crashes in some rare cases, for multithreaded environments. This can be used for a
1845 performance boost on applications that are single threaded.
1848 Make gdb output on native crashes more verbose.
1852 \fBMONO_LOG_LEVEL\fR
1853 The logging level, possible values are `error', `critical', `warning',
1854 `message', `info' and `debug'. See the DEBUGGING section for more
1858 Controls the domain of the Mono runtime that logging will apply to.
1859 If set, the log mask is changed to the set value. Possible values are
1860 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1861 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1862 "security" (e.g. Moonlight CoreCLR support) and "all".
1863 The default value is "all". Changing the mask value allows you to display only
1864 messages for a certain component. You can use multiple masks by comma
1865 separating them. For example to see config file messages and assembly loader
1866 messages set you mask to "asm,cfg".
1869 Controls where trace log messages are written. If not set then the messages go to stdout.
1870 If set, the string either specifies a path to a file that will have messages appended to
1871 it, or the string "syslog" in which case the messages will be written to the system log.
1872 Under Windows, this is simulated by writing to a file called "mono.log".
1873 \fBMONO_LOG_HEADER\fR
1874 Controls whether trace log messages not directed to syslog have the id, timestamp, and
1875 pid as the prefix to the log message. To enable a header this environment variable need
1879 Used for runtime tracing of method calls. The format of the comma separated
1888 disabled Trace output off upon start.
1891 You can toggle trace output on/off sending a SIGUSR2 signal to the program.
1893 \fBMONO_TRACE_LISTENER\fR
1894 If set, enables the System.Diagnostics.DefaultTraceListener, which will
1895 print the output of the System.Diagnostics Trace and Debug classes.
1896 It can be set to a filename, and to Console.Out or Console.Error to display
1897 output to standard output or standard error, respectively. If it's set to
1898 Console.Out or Console.Error you can append an optional prefix that will
1899 be used when writing messages like this: Console.Error:MyProgramName.
1900 See the System.Diagnostics.DefaultTraceListener documentation for more
1903 \fBMONO_WCF_TRACE\fR
1904 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.
1906 \fBMONO_XEXCEPTIONS\fR
1907 This throws an exception when a X11 error is encountered; by default a
1908 message is displayed but execution continues
1910 \fBMONO_XMLSERIALIZER_DEBUG\fR
1911 Set this value to 1 to prevent the serializer from removing the
1912 temporary files that are created for fast serialization; This might
1913 be useful when debugging.
1916 This is used in the System.Windows.Forms implementation when running
1917 with the X11 backend. This is used to debug problems in Windows.Forms
1918 as it forces all of the commands send to X11 server to be done
1919 synchronously. The default mode of operation is asynchronous which
1920 makes it hard to isolate the root of certain problems.
1923 When the the MONO_XDEBUG env var is set, debugging info for JITted
1924 code is emitted into a shared library, loadable into gdb. This enables,
1925 for example, to see managed frame names on gdb backtraces.
1927 \fBMONO_VERBOSE_METHOD\fR
1928 Enables the maximum JIT verbosity for the specified method. This is
1929 very helpfull to diagnose a miscompilation problems of a specific
1930 method. This can be a semicolon-separated list of method names to
1931 match. If the name is simple, this applies to any method with that
1932 name, otherwise you can use a mono method description (see the section
1933 METHOD DESCRIPTIONS).
1935 \fBMONO_JIT_DUMP_METHOD\fR
1936 Enables sending of the JITs intermediate representation for a specified
1937 method to the IdealGraphVisualizer tool.
1939 \fBMONO_VERBOSE_HWCAP\fR
1940 If set, makes the JIT output information about detected CPU features
1941 (such as SSE, CMOV, FCMOV, etc) to stdout.
1943 \fBMONO_CONSERVATIVE_HWCAP\fR
1944 If set, the JIT will not perform any hardware capability detection. This
1945 may be useful to pinpoint the cause of JIT issues. This is the default
1946 when Mono is built as an AOT cross compiler, so that the generated code
1947 will run on most hardware.
1949 If you want to use Valgrind, you will find the file `mono.supp'
1950 useful, it contains the suppressions for the GC which trigger
1951 incorrect warnings. Use it like this:
1953 valgrind --suppressions=mono.supp mono ...
1956 On some platforms, Mono can expose a set of DTrace probes (also known
1957 as user-land statically defined, USDT Probes).
1959 They are defined in the file `mono.d'.
1961 .B ves-init-begin, ves-init-end
1963 Begin and end of runtime initialization.
1965 .B method-compile-begin, method-compile-end
1967 Begin and end of method compilation.
1968 The probe arguments are class name, method name and signature,
1969 and in case of method-compile-end success or failure of compilation.
1973 Begin and end of Garbage Collection.
1975 To verify the availability of the probes, run:
1977 dtrace -P mono'$target' -l -c mono
1980 Mono's Ping implementation for detecting network reachability can
1981 create the ICMP packets itself without requiring the system ping
1982 command to do the work. If you want to enable this on Linux for
1983 non-root users, you need to give the Mono binary special permissions.
1985 As root, run this command:
1987 # setcap cap_net_raw=+ep /usr/bin/mono
1990 On Unix assemblies are loaded from the installation lib directory. If you set
1991 `prefix' to /usr, the assemblies will be located in /usr/lib. On
1992 Windows, the assemblies are loaded from the directory where mono and
1995 .B ~/.mono/aot-cache
1997 The directory for the ahead-of-time compiler demand creation
1998 assemblies are located.
2000 .B /etc/mono/config, ~/.mono/config
2002 Mono runtime configuration file. See the mono-config(5) manual page
2003 for more information.
2005 .B ~/.config/.mono/certs, /usr/share/.mono/certs
2007 Contains Mono certificate stores for users / machine. See the certmgr(1)
2008 manual page for more information on managing certificate stores and
2009 the mozroots(1) page for information on how to import the Mozilla root
2010 certificates into the Mono certificate store.
2012 .B ~/.mono/assemblies/ASSEMBLY/ASSEMBLY.config
2014 Files in this directory allow a user to customize the configuration
2015 for a given system assembly, the format is the one described in the
2016 mono-config(5) page.
2018 .B ~/.config/.mono/keypairs, /usr/share/.mono/keypairs
2020 Contains Mono cryptographic keypairs for users / machine. They can be
2021 accessed by using a CspParameters object with DSACryptoServiceProvider
2022 and RSACryptoServiceProvider classes.
2024 .B ~/.config/.isolatedstorage, ~/.local/share/.isolatedstorage, /usr/share/.isolatedstorage
2026 Contains Mono isolated storage for non-roaming users, roaming users and
2027 local machine. Isolated storage can be accessed using the classes from
2028 the System.IO.IsolatedStorage namespace.
2030 .B <assembly>.config
2032 Configuration information for individual assemblies is loaded by the
2033 runtime from side-by-side files with the .config files, see the
2034 http://www.mono-project.com/Config for more information.
2036 .B Web.config, web.config
2038 ASP.NET applications are configured through these files, the
2039 configuration is done on a per-directory basis. For more information
2040 on this subject see the http://www.mono-project.com/Config_system.web
2043 Mailing lists are listed at the
2044 http://www.mono-project.com/community/help/mailing-lists/
2046 http://www.mono-project.com
2049 \fBcertmgr\fR(1), \fBcert-sync\fR(1), \fBcsharp\fR(1),
2050 \fBgacutil\fR(1), \fBmcs\fR(1), \fBmonodis\fR(1),
2051 \fBmono-config\fR(5), \fBmono\-profilers\fR(1),
2052 \fBmprof\-report\fR(1), \fBpdb2mdb\fR(1), \fBxsp\fR(1),
2055 For more information on AOT:
2056 http://www.mono-project.com/docs/advanced/aot/
2058 For ASP.NET-related documentation, see the xsp(1) manual page