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 llvm-outfile=[filename]
250 Gives the path for the temporary LLVM bitcode file created during AOT.
252 Each AOT module will typically contain the code for inflated methods and wrappers that
253 are called by code in that module. In dedup mode, we identify and skip compiling all of those
254 methods. When using this mode with fullaot, dedup-include is required or these methods will
257 .I dedup-include=[filename]
258 In dedup-include mode, we are in the pass of compilation where we compile the methods
259 that we had previously skipped. All of them are emitted into the assembly that is passed
260 as this option. We consolidate the many duplicate skipped copies of the same method into one.
264 Print the architecture the AOT in this copy of Mono targets and quit.
267 Generates all required wrappers, so that it is possible to run --interpreter without
268 any code generation at runtime. This option only makes sense with \fBmscorlib.dll\fR.
271 .I depfile=[filename]
272 Outputs a gcc -M style dependency file.
275 mono_jit_set_aot_mode (MONO_AOT_MODE_INTERP);
280 Additional flags to pass to the C linker (if the current AOT mode calls for invoking it).
282 .I llvm-path=<PREFIX>
283 Same for the llvm tools 'opt' and 'llc'.
286 Instructs the AOT compiler to generate offline sequence points .msym files.
287 The generated .msym files will be stored into a subfolder of <PATH> named as the
291 Use the GNU style target triple <TRIPLE> to determine some code generation options, i.e.
292 --mtriple=armv7-linux-gnueabi will generate code that targets ARMv7. This is currently
293 only supported by the ARM backend. In LLVM mode, this triple is passed on to the LLVM
296 .I nimt-trampolines=[number]
297 When compiling in full aot mode, the IMT trampolines must be precreated
298 in the AOT image. You can add additional method trampolines with this argument.
301 .I ngsharedvt-trampolines=[number]
302 When compiling in full aot mode, the value type generic sharing trampolines must be precreated
303 in the AOT image. You can add additional method trampolines with this argument.
307 Instructs the AOT compiler to not output any debugging information.
310 This prevents the AOT compiler from generating a direct calls to a
311 method. The AOT compiler usually generates direct calls for certain
312 methods that do not require going through the PLT (for example,
313 methods that are known to not require a hook like a static
314 constructor) or call into simple internal calls.
316 .I nrgctx-trampolines=[number]
317 When compiling in full aot mode, the generic sharing trampolines must be precreated
318 in the AOT image. You can add additional method trampolines with this argument.
321 .I nrgctx-fetch-trampolines=[number]
322 When compiling in full aot mode, the generic sharing fetch trampolines must be precreated
323 in the AOT image. You can add additional method trampolines with this argument.
326 .I ntrampolines=[number]
327 When compiling in full aot mode, the method trampolines must be precreated
328 in the AOT image. You can add additional method trampolines with this argument.
331 .I outfile=[filename]
332 Instructs the AOT compiler to save the output to the specified file.
334 .I print-skipped-methods
335 If the AOT compiler cannot compile a method for any reason, enabling this flag
336 will output the skipped methods to the console.
339 Specify a file to use for profile-guided optimization. See the \fBAOT profiler\fR sub-section. To specify multiple files, include the
341 option multiple times.
344 AOT *only* the methods described in the files specified with the
346 option. See the \fBAOT profiler\fR sub-section.
348 .I readonly-value=namespace.typename.fieldname=type/value
349 Override the value of a static readonly field. Usually, during JIT
350 compilation, the static constructor is ran eagerly, so the value of
351 a static readonly field is known at compilation time and the compiler
352 can do a number of optimizations based on it. During AOT, instead, the static
353 constructor can't be ran, so this option can be used to set the value of such
354 a field and enable the same set of optimizations.
355 Type can be any of i1, i2, i4 for integers of the respective sizes (in bytes).
356 Note that signed/unsigned numbers do not matter here, just the storage size.
357 This option can be specified multiple times and it doesn't prevent the static
358 constructor for the type defining the field to execute with the usual rules
359 at runtime (hence possibly computing a different value for the field).
361 .I save-temps,keep-temps
362 Instructs the AOT compiler to keep temporary files.
365 This instructs the compiler to generate sequence point checks that
366 allow Mono's soft debugger to debug applications even on systems where
367 it is not possible to set breakpoints or to single step (certain
368 hardware configurations like the cell phones and video gaming
372 Create an ELF object file (.o) or .s file which can be statically linked into an
373 executable when embedding the mono runtime. When this option is used, the object file
374 needs to be registered with the embedded runtime using the mono_aot_register_module
375 function which takes as its argument the mono_aot_module_<ASSEMBLY NAME>_info global
376 symbol from the object file:
379 extern void *mono_aot_module_hello_info;
381 mono_aot_register_module (mono_aot_module_hello_info);
386 Print various stats collected during AOT compilation.
389 Explicitly specify path to store temporary files created during AOT compilation.
392 This is an experimental option for the AOT compiler to use multiple threads
393 when compiling the methods.
395 .I tool-prefix=<PREFIX>
396 Prepends <PREFIX> to the name of tools ran by the AOT compiler, i.e. 'as'/'ld'. For
397 example, --tool=prefix=arm-linux-gnueabi- will make the AOT compiler run
398 'arm-linux-gnueabi-as' instead of 'as'.
401 Prints additional information about type loading failures.
403 .I write-symbols,no-write-symbols
404 Instructs the AOT compiler to emit (or not emit) debug symbol information.
407 Instructs the AOT compiler tot no call opt when compiling with LLVM.
409 For more information about AOT, see: http://www.mono-project.com/docs/advanced/aot/
412 \fB--aot-path=PATH\fR
413 List of additional directories to search for AOT images.
415 \fB--apply-bindings=FILE\fR
416 Apply the assembly bindings from the specified configuration file when running
417 the AOT compiler. This is useful when compiling an auxiliary assembly that is
418 referenced by a main assembly that provides a configuration file. For example,
419 if app.exe uses lib.dll then in order to make the assembly bindings from
420 app.exe.config available when compiling lib.dll ahead of time, use:
422 mono --apply-bindings=app.exe.config --aot lib.dll
425 \fB--assembly-loader=MODE\fR
426 If mode is \fBstrict\fR, Mono will check that the public key token, culture and version
427 of a candidate assembly matches the requested strong name. If mode is \fBlegacy\fR, as
428 long as the name matches, the candidate will be allowed. \fBstrict\fR is the behavior
429 consistent with .NET Framework but may break some existing mono-based applications.
430 The default is \fBlegacy\fR.
432 \fB--attach=[options]\fR
433 Currently the only option supported by this command line argument is
434 \fBdisable\fR which disables the attach functionality.
436 \fB--config filename\fR
437 Load the specified configuration file instead of the default one(s).
438 The default files are /etc/mono/config and ~/.mono/config or the file
439 specified in the MONO_CONFIG environment variable, if set. See the
440 mono-config(5) man page for details on the format of this file.
442 \fB--debugger-agent=[options]\fR
443 This instructs the Mono runtime to
444 start a debugging agent inside the Mono runtime and connect it to a
445 client user interface will control the Mono process.
446 This option is typically used by IDEs, like the MonoDevelop or Visual Studio IDEs.
448 The configuration is specified using one of more of the following options:
454 Use this option to specify the IP address where your debugger client is
459 Specifies the diagnostics log level for
463 Used to specify the file where the log will be stored, it defaults to
467 Defaults to no, with the default option Mono will actively connect to the
468 host/port configured with the \fBaddress\fR option. If you set it to 'y', it
469 instructs the Mono runtime to start debugging in server mode, where Mono
470 actively waits for the debugger front end to connect to the Mono process.
471 Mono will print out to stdout the IP address and port where it is listening.
474 If set to yes, Mono will call \fBsetpgid(0, 0)\fR on startup, if that function
475 is available on the system. This is useful for ensuring that signals delivered
476 to a process that is executing the debuggee are not propagated to the debuggee,
477 e.g. when Ctrl-C sends \fBSIGINT\fR to the \fBsdb\fR tool.
480 Defaults to yes, with the default option Mono will suspend the vm on startup
481 until it connects successfully to a debugger front end. If you set it to 'n', in
482 conjunction with \fBserver=y\fR, it instructs the Mono runtime to run as normal,
483 while caching metadata to send to the debugger front end on connection..
485 .I transport=transport_name
487 This is used to specify the transport that the debugger will use to
488 communicate. It must be specified and currently requires this to
494 Configures the virtual machine to be better suited for desktop
495 applications. Currently this sets the GC system to avoid expanding
496 the heap as much as possible at the expense of slowing down garbage
500 This flag instructs the Mono runtime to not
501 generate any code at runtime and depend exclusively on the code
502 generated from using mono --aot=full previously. This is useful for
503 platforms that do not permit dynamic code generation, or if you need
504 to run assemblies that have been stripped of IL (for example using
507 Notice that this feature will abort execution at runtime if a codepath
508 in your program, or Mono's class libraries attempts to generate code
509 dynamically. You should test your software upfront and make sure that
510 you do not use any dynamic features.
512 \fB--full-aot-interp\fR
513 Same as --full-aot with fallback to the interpreter.
515 \fB--gc=boehm\fR, \fB--gc=sgen\fR
516 Selects the Garbage Collector engine for Mono to use, Boehm or SGen.
517 Currently this merely ensures that you are running either the
518 \fImono\fR or \fImono-sgen\fR commands. This flag can be set in the
519 \fBMONO_ENV_OPTIONS\fR environment variable to force all of your child
520 processes to use one particular kind of GC with the Mono runtime.
522 \fB--gc-debug=[options]\fR
523 Command line equivalent of the \fBMONO_GC_DEBUG\fR environment variable.
525 \fB--gc-params=[options]\fR
526 Command line equivalent of the \fBMONO_GC_PARAMS\fR environment variable.
528 \fB--arch=32\fR, \fB--arch=64\fR
529 (Mac OS X only): Selects the bitness of the Mono binary used, if
530 available. If the binary used is already for the selected bitness, nothing
531 changes. If not, the execution switches to a binary with the selected
532 bitness suffix installed side by side (for example, '/bin/mono --arch=64'
533 will switch to '/bin/mono64' iff '/bin/mono' is a 32-bit build).
535 \fB--help\fR, \fB-h\fR
536 Displays usage instructions.
539 The Mono runtime will use its interpreter to execute a given assembly.
540 The interpreter is usually slower than the JIT, but it can be useful on
541 platforms where code generation at runtime is not allowed.
544 This flag allows the Mono runtime to run assemblies
545 that have been stripped of IL, for example using mono-cil-strip. For this to
546 work, the assembly must have been AOT compiled with --aot=hybrid.
548 This flag is similar to --full-aot, but it does not disable the JIT. This means
549 you can use dynamic features such as System.Reflection.Emit.
552 If the Mono runtime has been compiled with LLVM support (not available
553 in all configurations), Mono will use the LLVM optimization and code
554 generation engine to JIT or AOT compile.
556 For more information, consult: http://www.mono-project.com/docs/advanced/mono-llvm/
559 When using a Mono that has been compiled with LLVM support, it forces
560 Mono to fallback to its JIT engine and not use the LLVM backend.
562 \fB--optimize=MODE\fR, \fB-O=MODE\fR
563 MODE is a comma separated list of optimizations. They also allow
564 optimizations to be turned off by prefixing the optimization name with
567 In general, Mono has been tuned to use the default set of flags,
568 before using these flags for a deployment setting, you might want to
569 actually measure the benefits of using them.
571 The following optimization flags are implemented in the core engine:
573 abcrem Array bound checks removal
574 all Turn on all optimizations
575 aot Usage of Ahead Of Time compiled code
576 branch Branch optimizations
577 cfold Constant folding
578 cmov Conditional moves [arch-dependency]
579 deadce Dead code elimination
580 consprop Constant propagation
581 copyprop Copy propagation
582 fcmov Fast x86 FP compares [arch-dependency]
583 float32 Perform 32-bit float arithmetic using 32-bit operations
584 gshared Enable generic code sharing.
585 inline Inline method calls
586 intrins Intrinsic method implementations
587 linears Linear scan global reg allocation
588 leaf Leaf procedures optimizations
589 loop Loop related optimizations
590 peephole Peephole postpass
591 precomp Precompile all methods before executing Main
592 sched Instruction scheduling
593 shared Emit per-domain code
594 sse2 SSE2 instructions on x86 [arch-dependency]
595 tailc Tail recursion and tail calls
598 For example, to enable all the optimization but dead code
599 elimination and inlining, you can use:
601 -O=all,-deadce,-inline
604 The flags that are flagged with [arch-dependency] indicate that the
605 given option if used in combination with Ahead of Time compilation
606 (--aot flag) would produce pre-compiled code that will depend on the
607 current CPU and might not be safely moved to another computer.
611 The following optimizations are supported
614 Requests that the runtime performn 32-bit floating point operations
615 using only 32-bits. By default the Mono runtime tries to use the
616 highest precision available for floating point operations, but while
617 this might render better results, the code might run slower. This
618 options also affects the code generated by the LLVM backend.
621 Controls whether the runtime should attempt to inline (the default),
622 or not inline methods invocations
625 \fB--response=FILE\fR
626 Provides a response file, this instructs the Mono command to read
627 other command line options from the specified file, as if the
628 options had been specified on the command line. Useful when you have
629 very long command lines.
631 \fB--runtime=VERSION\fR
632 Mono supports different runtime versions. The version used depends on the program
633 that is being run or on its configuration file (named program.exe.config). This option
634 can be used to override such autodetection, by forcing a different runtime version
635 to be used. Note that this should only be used to select a later compatible runtime
636 version than the one the program was compiled against. A typical usage is for
637 running a 1.1 program on a 2.0 version:
639 mono --runtime=v2.0.50727 program.exe
643 Configures the virtual machine to be better suited for server
644 operations (currently, allows a heavier threadpool initialization).
647 Instructs Mono to generate code using MAP_JIT on MacOS. Necessary for
648 bundled applications.
651 Verifies mscorlib and assemblies in the global
652 assembly cache for valid IL, and all user code for IL
655 This is different from \fB--security\fR's verifiable
656 or validil in that these options only check user code and skip
657 mscorlib and assemblies located on the global assembly cache.
659 \fB-V\fR, \fB--version\fR
660 Prints JIT version information (system configuration, release number
661 and branch names if available).
663 \fB--version=number\fR
664 Print version number only.
667 .SH DEVELOPMENT OPTIONS
668 The following options are used to help when developing a JITed application.
670 \fB--debug\fR, \fB--debug=OPTIONS\fR
671 Turns on the debugging mode in the runtime. If an assembly was
672 compiled with debugging information, it will produce line number
673 information for stack traces.
677 The optional OPTIONS argument is a comma separated list of debugging
678 options. These options are turned off by default since they generate
679 much larger and slower code at runtime.
681 The following options are supported:
684 Produces a detailed error when throwing a InvalidCastException. This
685 option needs to be enabled as this generates more verbose code at
689 Disable some JIT optimizations which are usually only disabled when
690 running inside the debugger. This can be helpful if you want to attach
691 to the running process with mdb.
694 Generate and register debugging information with gdb. This is only supported on some
695 platforms, and only when using gdb 7.0 or later.
699 \fB\-\-profile\fR[=\fIprofiler\fR[:\fIprofiler_args\fR]]\fR
700 Loads a profiler module with the given arguments. For more information,
701 see the \fBPROFILING\fR section.
703 This option can be used multiple times; each time will load an additional
706 \fB--trace[=expression]\fR
707 Shows method names as they are invoked. By default all methods are
710 The trace can be customized to include or exclude methods, classes or
711 assemblies. A trace expression is a comma separated list of targets,
712 each target can be prefixed with a minus sign to turn off a particular
713 target. The words `program', `all' and `disabled' have special
714 meaning. `program' refers to the main program being executed, and
715 `all' means all the method calls.
717 The `disabled' option is used to start up with tracing disabled. It
718 can be enabled at a later point in time in the program by sending the
719 SIGUSR2 signal to the runtime.
721 Assemblies are specified by their name, for example, to trace all
722 calls in the System assembly, use:
725 mono --trace=System app.exe
728 Classes are specified with the T: prefix. For example, to trace all
729 calls to the System.String class, use:
732 mono --trace=T:System.String app.exe
735 And individual methods are referenced with the M: prefix, and the
736 standard method notation:
739 mono --trace=M:System.Console:WriteLine app.exe
742 Exceptions can also be traced, it will cause a stack trace to be
743 printed every time an exception of the specified type is thrown.
744 The exception type can be specified with or without the namespace,
745 and to trace all exceptions, specify 'all' as the type name.
748 mono --trace=E:System.Exception app.exe
751 As previously noted, various rules can be specified at once:
754 mono --trace=T:System.String,T:System.Random app.exe
757 You can exclude pieces, the next example traces calls to
758 System.String except for the System.String:Concat method.
761 mono --trace=T:System.String,-M:System.String:Concat
764 You can trace managed to unmanaged transitions using
765 the wrapper qualifier:
768 mono --trace=wrapper app.exe
771 Finally, namespaces can be specified using the N: prefix:
774 mono --trace=N:System.Xml
778 \fB--no-x86-stack-align\fR
779 Don't align stack frames on the x86 architecture. By default, Mono
780 aligns stack frames to 16 bytes on x86, so that local floating point
781 and SIMD variables can be properly aligned. This option turns off the
782 alignment, which usually saves one instruction per call, but might
783 result in significantly lower floating point and SIMD performance.
786 Generate a JIT method map in a /tmp/perf-PID.map file. This file is then
787 used, for example, by the perf tool included in recent Linux kernels.
788 Each line in the file has:
791 HEXADDR HEXSIZE methodname
794 Currently this option is only supported on Linux.
795 .SH JIT MAINTAINER OPTIONS
796 The maintainer options are only used by those developing the runtime
797 itself, and not typically of interest to runtime users or developers.
799 \fB--bisect=optimization:filename\fR
800 This flag is used by the automatic optimization bug bisector. It
801 takes an optimization flag and a filename of a file containing a list
802 of full method names, one per line. When it compiles one of the
803 methods in the file it will use the optimization given, in addition to
804 the optimizations that are otherwise enabled. Note that if the
805 optimization is enabled by default, you should disable it with `-O`,
806 otherwise it will just apply to every method, whether it's in the file
810 Inserts a breakpoint before the method whose name is `method'
811 (namespace.class:methodname). Use `Main' as method name to insert a
812 breakpoint on the application's main method. You can use it also with
813 generics, for example "System.Collections.Generic.Queue`1:Peek"
816 Inserts a breakpoint on exceptions. This allows you to debug your
817 application with a native debugger when an exception is thrown.
820 This compiles a method (namespace.name:methodname), this is used for
821 testing the compiler performance or to examine the output of the code
825 Compiles all the methods in an assembly. This is used to test the
826 compiler performance or to examine the output of the code generator
828 \fB--graph=TYPE METHOD\fR
829 This generates a postscript file with a graph with the details about
830 the specified method (namespace.name:methodname). This requires `dot'
831 and ghostview to be installed (it expects Ghostview to be called
834 The following graphs are available:
836 cfg Control Flow Graph (CFG)
838 code CFG showing code
839 ssa CFG showing code after SSA translation
840 optcode CFG showing code after IR optimizations
843 Some graphs will only be available if certain optimizations are turned
847 Instruct the runtime on the number of times that the method specified
848 by --compile (or all the methods if --compile-all is used) to be
849 compiled. This is used for testing the code generator performance.
852 Displays information about the work done by the runtime during the
853 execution of an application.
855 \fB--wapi=hps|semdel\fR
856 Perform maintenance of the process shared data.
858 semdel will delete the global semaphore.
860 hps will list the currently used handles.
862 \fB-v\fR, \fB--verbose\fR
863 Increases the verbosity level, each time it is listed, increases the
864 verbosity level to include more information (including, for example,
865 a disassembly of the native code produced, code selector info etc.).
867 The Mono runtime allows external processes to attach to a running
868 process and load assemblies into the running program. To attach to
869 the process, a special protocol is implemented in the Mono.Management
872 With this support it is possible to load assemblies that have an entry
873 point (they are created with -target:exe or -target:winexe) to be
874 loaded and executed in the Mono process.
876 The code is loaded into the root domain, and it starts execution on
877 the special runtime attach thread. The attached program should
878 create its own threads and return after invocation.
880 This support allows for example debugging applications by having the
881 csharp shell attach to running processes.
883 The Mono runtime includes a profiler API that dynamically loaded
884 profiler modules and embedders can use to collect performance-related
885 data about an application. Profiler modules are loaded by passing the
886 \fB\-\-profile\fR command line argument to the Mono runtime.
888 Mono ships with a few profiler modules, of which the \fBlog\fR profiler
889 is the most feature-rich. It is also the default profiler if the
890 \fIprofiler\fR argument is not given, or if \fBdefault\fR is given.
891 It is possible to write your own profiler modules; see the
892 \fBCustom profilers\fR sub-section.
894 The log profiler can be used to collect a lot of information about
895 a program running in the Mono runtime. This data can be used (both
896 while the process is running and later) to do analyses of the
897 program behavior, determine resource usage, performance issues or
898 even look for particular execution patterns.
900 This is accomplished by logging the events provided by the Mono
901 runtime through the profiler API and periodically writing them to a
902 file which can later be inspected with the \fBmprof\-report\fR(1)
905 More information about how to use the log profiler is available on
906 the \fBmono\-profilers\fR(1) page, under the \fBLOG PROFILER\fR
907 section, as well as the \fBmprof\-report\fR(1) page.
908 .SS Coverage profiler
909 The code coverage profiler can instrument a program to help determine
910 which classes, methods, code paths, etc are actually executed. This
911 is most useful when running a test suite to determine whether the
912 tests actually cover the code they're expected to.
914 More information about how to use the coverage profiler is available
915 on the \fBmono\-profilers\fR(1) page, under the \fBCOVERAGE
918 The AOT profiler can help improve startup performance by logging
919 which generic instantiations are used by a program, which the AOT
920 compiler can then use to compile those instantiations ahead of time
921 so that they won't have to be JIT compiled at startup.
923 More information about how to use the AOT profiler is available on
924 the \fBmono\-profilers\fR(1) page, under the \fBAOT PROFILER\fR
927 Custom profiler modules can be loaded in exactly the same way as the
928 standard modules that ship with Mono. They can also access the same
929 profiler API to gather all kinds of information about the code being
932 For example, to use a third-party profiler called \fBcustom\fR, you
933 would load it like this:
937 mono --profile=custom program.exe
941 You could also pass arguments to it:
945 mono --profile=custom:arg1,arg2=arg3 program.exe
949 In the above example, Mono will load the profiler from the shared
950 library called \fIlibmono\-profiler\-custom.so\fR (name varies based
951 on platform, e.g., \fIlibmono\-profiler\-custom.dylib\fR on OS X).
952 This profiler module must be on your dynamic linker library path
953 (\fBLD_LIBRARY_PATH\fR on most systems, \fBDYLD_LIBRARY_PATH\fR on
956 For a sample of how to write your own custom profiler, look at the
957 \fIsamples/profiler/sample.c\fR file in the Mono source tree.
959 To debug managed applications, you can use the
961 command, a command line debugger.
963 It is possible to obtain a stack trace of all the active threads in
964 Mono by sending the QUIT signal to Mono, you can do this from the
965 command line, like this:
971 Where pid is the Process ID of the Mono process you want to examine.
972 The process will continue running afterwards, but its state is not
976 this is a last-resort mechanism for debugging applications and should
977 not be used to monitor or probe a production application. The
978 integrity of the runtime after sending this signal is not guaranteed
979 and the application might crash or terminate at any given point
982 The \fB--debug=casts\fR option can be used to get more detailed
983 information for Invalid Cast operations, it will provide information
984 about the types involved.
986 You can use the MONO_LOG_LEVEL and MONO_LOG_MASK environment variables
987 to get verbose debugging output about the execution of your
988 application within Mono.
992 environment variable if set, the logging level is changed to the set
993 value. Possible values are "error", "critical", "warning", "message",
994 "info", "debug". The default value is "error". Messages with a logging
995 level greater then or equal to the log level will be printed to
998 Use "info" to track the dynamic loading of assemblies.
1003 environment variable to limit the extent of the messages you get:
1004 If set, the log mask is changed to the set value. Possible values are
1005 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1006 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1007 "security" (e.g. Moonlight CoreCLR support), "threadpool" (thread pool generic),
1008 "io-selector" (async socket operations), "io-layer" (I/O layer - processes, files,
1009 sockets, events, semaphores, mutexes and handles), "io-layer-process",
1010 "io-layer-file", "io-layer-socket", "io-layer-event", "io-layer-semaphore",
1011 "io-layer-mutex", "io-layer-handle" and "all".
1012 The default value is "all". Changing the mask value allows you to display only
1013 messages for a certain component. You can use multiple masks by comma
1014 separating them. For example to see config file messages and assembly loader
1015 messages set you mask to "asm,cfg".
1017 The following is a common use to track down problems with P/Invoke:
1020 $ MONO_LOG_LEVEL="debug" MONO_LOG_MASK="dll" mono glue.exe
1024 .SH DEBUGGING WITH LLDB
1025 If you are using LLDB, you can use the
1027 script to print some internal data structures with it. To use this,
1032 command script import $PREFIX/lib/mono/lldb/mono.py
1035 Where $PREFIX is the prefix value that you used when you configured
1036 Mono (typically /usr).
1038 Once this is done, then you can inspect some Mono Runtime data structures,
1043 (MonoMethod *) $0 = 0x05026ac0 [mscorlib]System.OutOfMemoryException:.ctor()
1046 Mono's XML serialization engine by default will use a reflection-based
1047 approach to serialize which might be slow for continuous processing
1048 (web service applications). The serialization engine will determine
1049 when a class must use a hand-tuned serializer based on a few
1050 parameters and if needed it will produce a customized C# serializer
1051 for your types at runtime. This customized serializer then gets
1052 dynamically loaded into your application.
1054 You can control this with the MONO_XMLSERIALIZER_THS environment
1057 The possible values are
1059 to disable the use of a C# customized
1060 serializer, or an integer that is the minimum number of uses before
1061 the runtime will produce a custom serializer (0 will produce a
1062 custom serializer on the first access, 50 will produce a serializer on
1063 the 50th use). Mono will fallback to an interpreted serializer if the
1064 serializer generation somehow fails. This behavior can be disabled
1065 by setting the option
1067 (for example: MONO_XMLSERIALIZER_THS=0,nofallback).
1068 .SH ENVIRONMENT VARIABLES
1071 Turns off the garbage collection in Mono. This should be only used
1072 for debugging purposes
1075 (Also \fBhttp_proxy\fR) If set, web requests using the Mono
1076 Class Library will be automatically proxied through the given URL.
1077 Not supported on Windows, Mac OS, iOS or Android. See also \fBNO_PROXY\fR.
1080 When Mono is compiled with LLVM support, this instructs the runtime to
1081 stop using LLVM after the specified number of methods are JITed.
1082 This is a tool used in diagnostics to help isolate problems in the
1083 code generation backend. For example \fBLLVM_COUNT=10\fR would only
1084 compile 10 methods with LLVM and then switch to the Mono JIT engine.
1085 \fBLLVM_COUNT=0\fR would disable the LLVM engine altogether.
1087 \fBMONO_ASPNET_INHIBIT_SETTINGSMAP\fR
1088 Mono contains a feature which allows modifying settings in the .config files shipped
1089 with Mono by using config section mappers. The mappers and the mapping rules are
1090 defined in the $prefix/etc/mono/2.0/settings.map file and, optionally, in the
1091 settings.map file found in the top-level directory of your ASP.NET application.
1092 Both files are read by System.Web on application startup, if they are found at the
1093 above locations. If you don't want the mapping to be performed you can set this
1094 variable in your environment before starting the application and no action will
1097 \fBMONO_ASPNET_WEBCONFIG_CACHESIZE\fR
1098 Mono has a cache of ConfigSection objects for speeding up WebConfigurationManager
1099 queries. Its default size is 100 items, and when more items are needed, cache
1100 evictions start happening. If evictions are too frequent this could impose
1101 unnecessary overhead, which could be avoided by using this environment variable
1102 to set up a higher cache size (or to lower memory requirements by decreasing it).
1104 \fBMONO_CAIRO_DEBUG_DISPOSE\fR
1105 If set, causes Mono.Cairo to collect stack traces when objects are allocated,
1106 so that the finalization/Dispose warnings include information about the
1110 If set, this variable overrides the default system configuration directory
1111 ($PREFIX/etc). It's used to locate machine.config file.
1114 Sets the style of COM interop. If the value of this variable is "MS"
1115 Mono will use string marhsalling routines from the liboleaut32 for the
1116 BSTR type library, any other values will use the mono-builtin BSTR
1120 If set, this variable overrides the default runtime configuration file
1121 ($PREFIX/etc/mono/config). The --config command line options overrides the
1122 environment variable.
1125 Override the automatic cpu detection mechanism. Currently used only on arm.
1126 The format of the value is as follows:
1132 where V is the architecture number 4, 5, 6, 7 and the options can be currently be
1133 "thumb" or "thumb2". Example:
1136 MONO_CPU_ARCH="armv4 thumb" mono ...
1140 \fBMONO_ARM_FORCE_SOFT_FLOAT\fR
1141 When Mono is built with a soft float fallback on ARM and this variable is set to
1142 "1", Mono will always emit soft float code, even if a VFP unit is
1145 \fBMONO_DARWIN_USE_KQUEUE_FSW\fR
1146 Fall back on the kqueue FileSystemWatcher implementation in Darwin. The default is the FSEvent implementation.
1148 \fBMONO_DARWIN_WATCHER_MAXFDS\fR
1149 This is a debugging aid used to force limits on the kqueue FileSystemWatcher
1150 implementation in Darwin. There is no limit by default.
1152 \fBMONO_DISABLE_MANAGED_COLLATION\fR
1153 If this environment variable is `yes', the runtime uses unmanaged
1154 collation (which actually means no culture-sensitive collation). It
1155 internally disables managed collation functionality invoked via the
1156 members of System.Globalization.CompareInfo class. Collation is
1159 \fBMONO_DISABLE_SHARED_AREA\fR
1160 Unix only: If set, disable usage of shared memory for exposing
1161 performance counters. This means it will not be possible to both
1162 externally read performance counters from this processes or read
1163 those of external processes.
1166 When set, enables the use of a fully managed DNS resolver instead of the
1167 regular libc functions. This resolver performs much better when multiple
1168 queries are run in parallel.
1170 Note that /etc/nsswitch.conf will be ignored.
1172 \fBMONO_EGD_SOCKET\fR
1173 For platforms that do not otherwise have a way of obtaining random bytes
1174 this can be set to the name of a file system socket on which an egd or
1175 prngd daemon is listening.
1177 \fBMONO_ENABLE_AIO\fR
1178 If set, tells mono to attempt using native asynchronous I/O services. If not
1179 set, a default select/poll implementation is used. Currently epoll and kqueue
1182 \fBMONO_THREADS_SUSPEND\fR
1183 Selects a mechanism that Mono will use to suspend threads. May be set to
1184 "preemptive", "coop", or "hybrid". Threads may need to be suspended by the
1185 debugger, or using some .NET threading APIs, and most commonly when the SGen
1186 garbage collector needs to stop all threads during a critical phase of garbage
1187 collection. Preemptive mode is the mode that Mono has used historically, going
1188 back to the Boehm days, where the garbage collector would run at any point and
1189 suspend execution of all threads as required to perform a garbage collection.
1190 The cooperative mode on the other hand requires the cooperation of all threads
1191 to stop at a safe point. This makes for an easier to debug garbage collector.
1192 As of Mono 4.3.0 it is a work in progress, and while it works, it has not been
1193 used extensively. This option enables the feature and allows us to find spots
1194 that need to be tuned for this mode of operation. Hybrid mode is a combination
1195 of the two that retains better compatability with scenarios where Mono is
1196 embedded in another application: threads that are running managed code or code
1197 that comprises the Mono runtime will be cooperatively suspended, while threads
1198 running embedder code will be preemptively suspended.
1200 Alternatively, coop and hybrid mode can be enabled at compile time by using the
1201 --enable-cooperative-suspend or --enable-hybrid-suspend flags, respectively,
1202 when calling configure. The \fBMONO_THREADS_SUSPEND\fR environment variable
1203 takes priority over the compiled default.
1205 \fBMONO_ENABLE_COOP_SUSPEND\fR
1206 This environment variable is obsolete, but retained for backward compatibility.
1207 Use \fBMONO_THREADS_SUSPEND\fR set to "coop" instead. Note that if configure flags
1208 were provided to enable cooperative or hybrid suspend, this variable is ignored.
1210 \fBMONO_ENV_OPTIONS\fR
1211 This environment variable allows you to pass command line arguments to
1212 a Mono process through the environment. This is useful for example
1213 to force all of your Mono processes to use LLVM or SGEN without having
1214 to modify any launch scripts.
1216 \fBMONO_SDB_ENV_OPTIONS\fR
1217 Used to pass extra options to the debugger agent in the runtime, as they were passed
1218 using --debugger-agent=.
1220 \fBMONO_EVENTLOG_TYPE\fR
1221 Sets the type of event log provider to use (for System.Diagnostics.EventLog).
1223 Possible values are:
1228 Persists event logs and entries to the local file system.
1230 The directory in which to persist the event logs, event sources and entries
1231 can be specified as part of the value.
1233 If the path is not explicitly set, it defaults to "/var/lib/mono/eventlog"
1234 on unix and "%APPDATA%\mono\eventlog" on Windows.
1239 Uses the native win32 API to write events and registers event logs and
1240 event sources in the registry. This is only available on Windows.
1242 On Unix, the directory permission for individual event log and event source
1243 directories is set to 777 (with +t bit) allowing everyone to read and write
1244 event log entries while only allowing entries to be deleted by the user(s)
1249 Silently discards any events.
1252 The default is "null" on Unix (and versions of Windows before NT), and
1253 "win32" on Windows NT (and higher).
1256 \fBMONO_EXTERNAL_ENCODINGS\fR
1257 If set, contains a colon-separated list of text encodings to try when
1258 turning externally-generated text (e.g. command-line arguments or
1259 filenames) into Unicode. The encoding names come from the list
1260 provided by iconv, and the special case "default_locale" which refers
1261 to the current locale's default encoding.
1263 When reading externally-generated text strings UTF-8 is tried first,
1264 and then this list is tried in order with the first successful
1265 conversion ending the search. When writing external text (e.g. new
1266 filenames or arguments to new processes) the first item in this list
1267 is used, or UTF-8 if the environment variable is not set.
1269 The problem with using MONO_EXTERNAL_ENCODINGS to process your
1270 files is that it results in a problem: although its possible to get
1271 the right file name it is not necessarily possible to open the file.
1272 In general if you have problems with encodings in your filenames you
1273 should use the "convmv" program.
1275 \fBMONO_GC_PARAMS\fR
1276 When using Mono with the SGen garbage collector this variable controls
1277 several parameters of the collector. The variable's value is a comma
1278 separated list of words.
1282 \fBmax-heap-size=\fIsize\fR
1283 Sets the maximum size of the heap. The size is specified in bytes and must
1284 be a power of two. The suffixes `k', `m' and `g' can be used to
1285 specify kilo-, mega- and gigabytes, respectively. The limit is the sum
1286 of the nursery, major heap and large object heap. Once the limit is reached
1287 the application will receive OutOfMemoryExceptions when trying to allocate.
1288 Not the full extent of memory set in max-heap-size could be available to
1289 satisfy a single allocation due to internal fragmentation. By default heap
1290 limits is disabled and the GC will try to use all available memory.
1292 \fBnursery-size=\fIsize\fR
1293 Sets the size of the nursery. The size is specified in bytes and must
1294 be a power of two. The suffixes `k', `m' and `g' can be used to
1295 specify kilo-, mega- and gigabytes, respectively. The nursery is the
1296 first generation (of two). A larger nursery will usually speed up the
1297 program but will obviously use more memory. The default nursery size
1300 \fBmajor=\fIcollector\fR
1301 Specifies which major collector to use.
1302 Options are `marksweep' for the Mark&Sweep collector, `marksweep-conc'
1303 for concurrent Mark&Sweep and `marksweep-conc-par' for parallel and
1304 concurrent Mark&Sweep. The concurrent Mark&Sweep collector is the default.
1306 \fBmode=balanced|throughput|pause\fR[:\fImax-pause\fR]
1307 Specifies what should be the garbage collector's target. The `throughput'
1308 mode aims to reduce time spent in the garbage collector and improve
1309 application speed, the `pause' mode aims to keep pause times to a minimum
1310 and it receives the argument \fImax-pause\fR which specifies the maximum
1311 pause time in milliseconds that is acceptable and the `balanced' mode
1312 which is a general purpose optimal mode.
1314 \fBsoft-heap-limit=\fIsize\fR
1315 Once the heap size gets larger than this size, ignore what the default
1316 major collection trigger metric says and only allow four nursery size's
1317 of major heap growth between major collections.
1319 \fBevacuation-threshold=\fIthreshold\fR
1320 Sets the evacuation threshold in percent. This option is only available
1321 on the Mark&Sweep major collectors. The value must be an
1322 integer in the range 0 to 100. The default is 66. If the sweep phase of
1323 the collection finds that the occupancy of a specific heap block type is
1324 less than this percentage, it will do a copying collection for that block
1325 type in the next major collection, thereby restoring occupancy to close
1326 to 100 percent. A value of 0 turns evacuation off.
1328 \fB(no-)lazy-sweep\fR
1329 Enables or disables lazy sweep for the Mark&Sweep collector. If
1330 enabled, the sweeping of individual major heap blocks is done
1331 piecemeal whenever the need arises, typically during nursery
1332 collections. Lazy sweeping is enabled by default.
1334 \fB(no-)concurrent-sweep\fR
1335 Enables or disables concurrent sweep for the Mark&Sweep collector. If
1336 enabled, the iteration of all major blocks to determine which ones can
1337 be freed and which ones have to be kept and swept, is done
1338 concurrently with the running program. Concurrent sweeping is enabled
1341 \fBstack-mark=\fImark-mode\fR
1342 Specifies how application threads should be scanned. Options are
1343 `precise` and `conservative`. Precise marking allow the collector
1344 to know what values on stack are references and what are not.
1345 Conservative marking threats all values as potentially references
1346 and leave them untouched. Precise marking reduces floating garbage
1347 and can speed up nursery collection and allocation rate, it has
1348 the downside of requiring a significant extra memory per compiled
1349 method. The right option, unfortunately, requires experimentation.
1351 \fBsave-target-ratio=\fIratio\fR
1352 Specifies the target save ratio for the major collector. The collector
1353 lets a given amount of memory to be promoted from the nursery due to
1354 minor collections before it triggers a major collection. This amount
1355 is based on how much memory it expects to free. It is represented as
1356 a ratio of the size of the heap after a major collection.
1357 Valid values are between 0.1 and 2.0. The default is 0.5.
1358 Smaller values will keep the major heap size smaller but will trigger
1359 more major collections. Likewise, bigger values will use more memory
1360 and result in less frequent major collections.
1361 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1363 \fBdefault-allowance-ratio=\fIratio\fR
1364 Specifies the default allocation allowance when the calculated size
1365 is too small. The allocation allowance is how much memory the collector
1366 let be promoted before triggered a major collection.
1367 It is a ratio of the nursery size.
1368 Valid values are between 1.0 and 10.0. The default is 4.0.
1369 Smaller values lead to smaller heaps and more frequent major collections.
1370 Likewise, bigger values will allow the heap to grow faster but use
1371 more memory when it reaches a stable size.
1372 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1374 \fBminor=\fIminor-collector\fR
1375 Specifies which minor collector to use. Options are `simple' which
1376 promotes all objects from the nursery directly to the old generation,
1377 `simple-par' which has same promotion behavior as `simple' but using
1378 multiple workers and `split' which lets objects stay longer on the nursery
1381 \fBalloc-ratio=\fIratio\fR
1382 Specifies the ratio of memory from the nursery to be use by the alloc space.
1383 This only can only be used with the split minor collector.
1384 Valid values are integers between 1 and 100. Default is 60.
1386 \fBpromotion-age=\fIage\fR
1387 Specifies the required age of an object must reach inside the nursery before
1388 been promoted to the old generation. This only can only be used with the
1389 split minor collector.
1390 Valid values are integers between 1 and 14. Default is 2.
1392 \fB(no-)cementing\fR
1393 Enables or disables cementing. This can dramatically shorten nursery
1394 collection times on some benchmarks where pinned objects are referred
1395 to from the major heap.
1397 \fBallow-synchronous-major\fR
1398 This forbids the major collector from performing synchronous major collections.
1399 The major collector might want to do a synchronous collection due to excessive
1400 fragmentation. Disabling this might trigger OutOfMemory error in situations that
1401 would otherwise not happen.
1406 When using Mono with the SGen garbage collector this environment
1407 variable can be used to turn on various debugging features of the
1408 collector. The value of this variable is a comma separated list of
1409 words. Do not use these options in production.
1414 Sets the debug level to the specified number.
1416 \fBprint-allowance\fR
1417 After each major collection prints memory consumption for before and
1418 after the collection and the allowance for the minor collector, i.e. how
1419 much the heap is allowed to grow from minor collections before the next
1420 major collection is triggered.
1423 Gathers statistics on the classes whose objects are pinned in the
1424 nursery and for which global remset entries are added. Prints those
1425 statistics when shutting down.
1427 \fBcollect-before-allocs\fR
1429 \fBcheck-remset-consistency\fR
1430 This performs a remset consistency check at various opportunities, and
1431 also clears the nursery at collection time, instead of the default,
1432 when buffers are allocated (clear-at-gc). The consistency check
1433 ensures that there are no major to minor references that are not on
1434 the remembered sets.
1436 \fBmod-union-consistency-check\fR
1437 Checks that the mod-union cardtable is consistent before each
1438 finishing major collection pause. This check is only applicable to
1439 concurrent major collectors.
1441 \fBcheck-mark-bits\fR
1442 Checks that mark bits in the major heap are consistent at the end of
1443 each major collection. Consistent mark bits mean that if an object is
1444 marked, all objects that it had references to must also be marked.
1446 \fBcheck-nursery-pinned\fR
1447 After nursery collections, and before starting concurrent collections,
1448 check whether all nursery objects are pinned, or not pinned -
1449 depending on context. Does nothing when the split nursery collector
1452 \fBxdomain-checks\fR
1453 Performs a check to make sure that no references are left to an
1456 \fBclear-at-tlab-creation\fR
1457 Clears the nursery incrementally when the thread local allocation
1458 buffers (TLAB) are created. The default setting clears the whole
1461 \fBdebug-clear-at-tlab-creation\fR
1462 Clears the nursery incrementally when the thread local allocation
1463 buffers (TLAB) are created, but at GC time fills it with the byte
1464 `0xff`, which should result in a crash more quickly if
1465 `clear-at-tlab-creation` doesn't work properly.
1468 This clears the nursery at GC time instead of doing it when the thread
1469 local allocation buffer (TLAB) is created. The default is to clear
1470 the nursery at TLAB creation time.
1473 Don't do minor collections. If the nursery is full, a major collection
1474 is triggered instead, unless it, too, is disabled.
1477 Don't do major collections.
1479 \fBconservative-stack-mark\fR
1480 Forces the GC to scan the stack conservatively, even if precise
1481 scanning is available.
1483 \fBno-managed-allocator\fR
1484 Disables the managed allocator.
1486 \fBcheck-scan-starts\fR
1487 If set, does a plausibility check on the scan_starts before and after each collection
1489 \fBverify-nursery-at-minor-gc\fR
1490 If set, does a complete object walk of the nursery at the start of each minor collection.
1492 \fBdump-nursery-at-minor-gc\fR
1493 If set, dumps the contents of the nursery at the start of each minor collection. Requires
1494 verify-nursery-at-minor-gc to be set.
1496 \fBheap-dump=\fIfile\fR
1497 Dumps the heap contents to the specified file. To visualize the
1498 information, use the mono-heapviz tool.
1500 \fBbinary-protocol=\fIfile\fR
1501 Outputs the debugging output to the specified file. For this to
1502 work, Mono needs to be compiled with the BINARY_PROTOCOL define on
1503 sgen-gc.c. You can then use this command to explore the output
1505 sgen-grep-binprot 0x1234 0x5678 < file
1508 \fBnursery-canaries\fR
1509 If set, objects allocated in the nursery are suffixed with a canary (guard)
1510 word, which is checked on each minor collection. Can be used to detect/debug
1511 heap corruption issues.
1514 \fBdo-not-finalize(=\fIclasses\fB)\fR
1515 If enabled, finalizers will not be run. Everything else will be
1516 unaffected: finalizable objects will still be put into the
1517 finalization queue where they survive until they're scheduled to
1518 finalize. Once they're not in the queue anymore they will be
1519 collected regularly. If a list of comma-separated class names is
1520 given, only objects from those classes will not be finalized.
1523 \fBlog-finalizers\fR
1524 Log verbosely around the finalization process to aid debugging.
1528 \fBMONO_GAC_PREFIX\fR
1529 Provides a prefix the runtime uses to look for Global Assembly Caches.
1530 Directories are separated by the platform path separator (colons on
1531 unix). MONO_GAC_PREFIX should point to the top directory of a prefixed
1532 install. Or to the directory provided in the gacutil /gacdir command. Example:
1533 .B /home/username/.mono:/usr/local/mono/
1536 Enables some filename rewriting support to assist badly-written
1537 applications that hard-code Windows paths. Set to a colon-separated
1538 list of "drive" to strip drive letters, or "case" to do
1539 case-insensitive file matching in every directory in a path. "all"
1540 enables all rewriting methods. (Backslashes are always mapped to
1541 slashes if this variable is set to a valid option).
1544 For example, this would work from the shell:
1547 MONO_IOMAP=drive:case
1551 If you are using mod_mono to host your web applications, you can use
1554 directive instead, like this:
1557 MonoIOMAP <appalias> all
1560 See mod_mono(8) for more details.
1563 When Mono is using the LLVM code generation backend you can use this
1564 environment variable to pass code generation options to the LLVM
1567 \fBMONO_MANAGED_WATCHER\fR
1568 If set to "disabled", System.IO.FileSystemWatcher will use a file watcher
1569 implementation which silently ignores all the watching requests.
1570 If set to any other value, System.IO.FileSystemWatcher will use the default
1571 managed implementation (slow). If unset, mono will try to use inotify, FAM,
1572 Gamin, kevent under Unix systems and native API calls on Windows, falling
1573 back to the managed implementation on error.
1575 \fBMONO_MESSAGING_PROVIDER\fR
1576 Mono supports a plugin model for its implementation of System.Messaging making
1577 it possible to support a variety of messaging implementations (e.g. AMQP, ActiveMQ).
1578 To specify which messaging implementation is to be used the evironement variable
1579 needs to be set to the full class name for the provider. E.g. to use the RabbitMQ based
1580 AMQP implementation the variable should be set to:
1583 Mono.Messaging.RabbitMQ.RabbitMQMessagingProvider,Mono.Messaging.RabbitMQ
1586 If set causes the mono process to be bound to a single processor. This may be
1587 useful when debugging or working around race conditions.
1590 Disable inlining of thread local accesses. Try setting this if you get a segfault
1591 early on in the execution of mono.
1594 Provides a search path to the runtime where to look for library
1595 files. This is a tool convenient for debugging applications, but
1596 should not be used by deployed applications as it breaks the assembly
1597 loader in subtle ways.
1599 Directories are separated by the platform path separator (colons on unix). Example:
1600 .B /home/username/lib:/usr/local/mono/lib
1602 Relative paths are resolved based on the launch-time current directory.
1604 Alternative solutions to MONO_PATH include: installing libraries into
1605 the Global Assembly Cache (see gacutil(1)) or having the dependent
1606 libraries side-by-side with the main executable.
1608 For a complete description of recommended practices for application
1610 http://www.mono-project.com/docs/getting-started/application-deployment/
1612 \fBMONO_SHARED_DIR\fR
1613 If set its the directory where the ".wapi" handle state is stored.
1614 This is the directory where the Windows I/O Emulation layer stores its
1615 shared state data (files, events, mutexes, pipes). By default Mono
1616 will store the ".wapi" directory in the users's home directory.
1618 \fBMONO_SHARED_HOSTNAME\fR
1619 Uses the string value of this variable as a replacement for the host name when
1620 creating file names in the ".wapi" directory. This helps if the host name of
1621 your machine is likely to be changed when a mono application is running or if
1622 you have a .wapi directory shared among several different computers.
1624 Mono typically uses the hostname to create the files that are used to
1625 share state across multiple Mono processes. This is done to support
1626 home directories that might be shared over the network.
1628 \fBMONO_STRICT_IO_EMULATION\fR
1629 If set, extra checks are made during IO operations. Currently, this
1630 includes only advisory locks around file writes.
1632 \fBMONO_TLS_PROVIDER\fR
1633 This environment variable controls which TLS/SSL provider Mono will
1634 use. The options are usually determined by the operating system where
1635 Mono was compiled and the configuration options that were used for
1641 Uses the default TLS stack that the Mono runtime was configured with.
1642 Usually this is configured to use Apple's SSL stack on Apple
1643 platforms, and Boring SSL on other platforms.
1646 Forces the use of the Apple SSL stack, only works on Apple platforms.
1649 Forces the use of the BoringSSL stack. See
1650 https://opensource.google.com/projects/boringssl for more information
1654 This is the old Mono stack, which only supports SSL and TLS up to
1655 version 1.0. It is deprecated and will be removed in the future.
1658 \fBMONO_TLS_SESSION_CACHE_TIMEOUT\fR
1659 The time, in seconds, that the SSL/TLS session cache will keep it's entry to
1660 avoid a new negotiation between the client and a server. Negotiation are very
1661 CPU intensive so an application-specific custom value may prove useful for
1662 small embedded systems.
1664 The default is 180 seconds.
1666 \fBMONO_THREADS_PER_CPU\fR
1667 The minimum number of threads in the general threadpool will be
1668 MONO_THREADS_PER_CPU * number of CPUs. The default value for this
1671 \fBMONO_XMLSERIALIZER_THS\fR
1672 Controls the threshold for the XmlSerializer to produce a custom
1673 serializer for a given class instead of using the Reflection-based
1674 interpreter. The possible values are `no' to disable the use of a
1675 custom serializer or a number to indicate when the XmlSerializer
1676 should start serializing. The default value is 50, which means that
1677 the a custom serializer will be produced on the 50th use.
1679 \fBMONO_X509_REVOCATION_MODE\fR
1680 Sets the revocation mode used when validating a X509 certificate chain (https,
1681 ftps, smtps...). The default is 'nocheck', which performs no revocation check
1682 at all. The other possible values are 'offline', which performs CRL check (not
1683 implemented yet) and 'online' which uses OCSP and CRL to verify the revocation
1684 status (not implemented yet).
1687 (Also \fBno_proxy\fR) If both \fBHTTP_PROXY\fR and \fBNO_PROXY\fR are
1688 set, \fBNO_PROXY\fR will be treated as a comma-separated list of "bypass" domains
1689 which will not be sent through the proxy. Domains in \fBNO_PROXY\fR may contain
1690 wildcards, as in "*.mono-project.com" or "build????.local". Not supported on
1691 Windows, Mac OS, iOS or Android.
1692 .SH ENVIRONMENT VARIABLES FOR DEBUGGING
1694 \fBMONO_ASPNET_NODELETE\fR
1695 If set to any value, temporary source files generated by ASP.NET support
1696 classes will not be removed. They will be kept in the user's temporary
1700 If set, enables some features of the runtime useful for debugging.
1701 This variable should contain a comma separated list of debugging options.
1702 Currently, the following options are supported:
1706 \fBalign-small-structs\fR
1707 Enables small structs alignment to 4/8 bytes.
1709 \fBarm-use-fallback-tls\fR
1710 When this option is set on ARM, a fallback thread local store will be used instead
1711 of the default fast thread local storage primitives.
1713 \fBbreak-on-unverified\fR
1714 If this variable is set, when the Mono VM runs into a verification
1715 problem, instead of throwing an exception it will break into the
1716 debugger. This is useful when debugging verifier problems
1719 This option can be used to get more detailed information from
1720 InvalidCast exceptions, it will provide information about the types
1723 \fBcheck-pinvoke-callconv\fR
1724 This option causes the runtime to check for calling convention
1725 mismatches when using pinvoke, i.e. mixing cdecl/stdcall. It only
1726 works on windows. If a mismatch is detected, an
1727 ExecutionEngineException is thrown.
1729 \fBcollect-pagefault-stats\fR
1730 Collects information about pagefaults. This is used internally to
1731 track the number of page faults produced to load metadata. To display
1732 this information you must use this option with "--stats" command line
1735 \fBdebug-domain-unload\fR
1736 When this option is set, the runtime will invalidate the domain memory
1737 pool instead of destroying it.
1739 \fBdisable_omit_fp\fR
1740 Disables a compiler optimization where the frame pointer is omitted
1741 from the stack. This optimization can interact badly with debuggers.
1743 \fBdont-free-domains\fR
1744 This is an Optimization for multi-AppDomain applications (most
1745 commonly ASP.NET applications). Due to internal limitations Mono,
1746 Mono by default does not use typed allocations on multi-appDomain
1747 applications as they could leak memory when a domain is unloaded.
1749 Although this is a fine default, for applications that use more than
1750 on AppDomain heavily (for example, ASP.NET applications) it is worth
1751 trading off the small leaks for the increased performance
1752 (additionally, since ASP.NET applications are not likely going to
1753 unload the application domains on production systems, it is worth
1754 using this feature).
1756 \fBdyn-runtime-invoke\fR
1757 Instructs the runtime to try to use a generic runtime-invoke wrapper
1758 instead of creating one invoke wrapper.
1760 \fBexplicit-null-checks\fR
1761 Makes the JIT generate an explicit NULL check on variable dereferences
1762 instead of depending on the operating system to raise a SIGSEGV or
1763 another form of trap event when an invalid memory location is
1767 Equivalent to setting the \fBMONO_XDEBUG\fR variable, this emits
1768 symbols into a shared library as the code is JITed that can be loaded
1769 into GDB to inspect symbols.
1771 \fBgen-seq-points\fR
1772 Automatically generates sequence points where the
1773 IL stack is empty. These are places where the debugger can set a
1776 \fBno-compact-seq-points\fR
1777 Unless the option is used, the runtime generates sequence points data that
1778 maps native offsets to IL offsets. Sequence point data is used to
1779 display IL offset in stacktraces. Stacktraces with IL offsets can be
1780 symbolicated using mono-symbolicate tool.
1783 Captures the interrupt signal (Control-C) and displays a stack trace
1784 when pressed. Useful to find out where the program is executing at a
1785 given point. This only displays the stack trace of a single thread.
1788 Instructs the runtime to initialize the stack with
1789 some known values (0x2a on x86-64) at the start of a method to assist
1790 in debuggin the JIT engine.
1792 \fBkeep-delegates\fR
1793 This option will leak delegate trampolines that are no longer
1794 referenced as to present the user with more information about a
1795 delegate misuse. Basically a delegate instance might be created,
1796 passed to unmanaged code, and no references kept in managed code,
1797 which will garbage collect the code. With this option it is possible
1798 to track down the source of the problems.
1800 \fBno-gdb-backtrace\fR
1801 This option will disable the GDB backtrace emitted by the runtime
1802 after a SIGSEGV or SIGABRT in unmanaged code.
1804 \fBpartial-sharing\fR
1805 When this option is set, the runtime can share generated code between
1806 generic types effectively reducing the amount of code generated.
1808 \fBreverse-pinvoke-exceptions
1809 This option will cause mono to abort with a descriptive message when
1810 during stack unwinding after an exception it reaches a native stack
1811 frame. This happens when a managed delegate is passed to native code,
1812 and the managed delegate throws an exception. Mono will normally try
1813 to unwind the stack to the first (managed) exception handler, and it
1814 will skip any native stack frames in the process. This leads to
1815 undefined behaviour (since mono doesn't know how to process native
1816 frames), leaks, and possibly crashes too.
1818 \fBsingle-imm-size\fR
1819 This guarantees that each time managed code is compiled the same
1820 instructions and registers are used, regardless of the size of used
1823 \fBsoft-breakpoints\fR
1824 This option allows using single-steps and breakpoints in hardware
1825 where we cannot do it with signals.
1827 \fBsuspend-on-native-crash\fR
1828 This option will suspend the program when a native crash occurs (SIGSEGV, SIGILL, ...).
1829 This is useful for debugging crashes which do not happen under gdb,
1830 since a live process contains more information than a core file.
1832 \fBsuspend-on-sigsegv\fR
1833 Same as \fBsuspend-on-native-crash\fR.
1835 \fBsuspend-on-exception\fR
1836 This option will suspend the program when an exception occurs.
1838 \fBsuspend-on-unhandled\fR
1839 This option will suspend the program when an unhandled exception occurs.
1841 \fBthread-dump-dir=DIR\fR
1842 Use DIR for storage thread dumps created by SIGQUIT.
1845 Make gdb output on native crashes more verbose.
1849 \fBMONO_LOG_LEVEL\fR
1850 The logging level, possible values are `error', `critical', `warning',
1851 `message', `info' and `debug'. See the DEBUGGING section for more
1855 Controls the domain of the Mono runtime that logging will apply to.
1856 If set, the log mask is changed to the set value. Possible values are
1857 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1858 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1859 "security" (e.g. Moonlight CoreCLR support) and "all".
1860 The default value is "all". Changing the mask value allows you to display only
1861 messages for a certain component. You can use multiple masks by comma
1862 separating them. For example to see config file messages and assembly loader
1863 messages set you mask to "asm,cfg".
1866 Controls where trace log messages are written. If not set then the messages go to stdout.
1867 If set, the string either specifies a path to a file that will have messages appended to
1868 it, or the string "syslog" in which case the messages will be written to the system log.
1869 Under Windows, this is simulated by writing to a file called "mono.log".
1870 \fBMONO_LOG_HEADER\fR
1871 Controls whether trace log messages not directed to syslog have the id, timestamp, and
1872 pid as the prefix to the log message. To enable a header this environment variable need
1876 Used for runtime tracing of method calls. The format of the comma separated
1885 disabled Trace output off upon start.
1888 You can toggle trace output on/off sending a SIGUSR2 signal to the program.
1890 \fBMONO_TRACE_LISTENER\fR
1891 If set, enables the System.Diagnostics.DefaultTraceListener, which will
1892 print the output of the System.Diagnostics Trace and Debug classes.
1893 It can be set to a filename, and to Console.Out or Console.Error to display
1894 output to standard output or standard error, respectively. If it's set to
1895 Console.Out or Console.Error you can append an optional prefix that will
1896 be used when writing messages like this: Console.Error:MyProgramName.
1897 See the System.Diagnostics.DefaultTraceListener documentation for more
1900 \fBMONO_WCF_TRACE\fR
1901 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.
1903 \fBMONO_XEXCEPTIONS\fR
1904 This throws an exception when a X11 error is encountered; by default a
1905 message is displayed but execution continues
1907 \fBMONO_XMLSERIALIZER_DEBUG\fR
1908 Set this value to 1 to prevent the serializer from removing the
1909 temporary files that are created for fast serialization; This might
1910 be useful when debugging.
1913 This is used in the System.Windows.Forms implementation when running
1914 with the X11 backend. This is used to debug problems in Windows.Forms
1915 as it forces all of the commands send to X11 server to be done
1916 synchronously. The default mode of operation is asynchronous which
1917 makes it hard to isolate the root of certain problems.
1920 When the the MONO_XDEBUG env var is set, debugging info for JITted
1921 code is emitted into a shared library, loadable into gdb. This enables,
1922 for example, to see managed frame names on gdb backtraces.
1924 \fBMONO_VERBOSE_METHOD\fR
1925 Enables the maximum JIT verbosity for the specified method. This is
1926 very helpfull to diagnose a miscompilation problems of a specific
1927 method. This can be a semicolon-separated list of method names to
1928 match. If the name is simple, this applies to any method with that
1929 name, otherwise you can use a mono method description (see the section
1930 METHOD DESCRIPTIONS).
1932 \fBMONO_JIT_DUMP_METHOD\fR
1933 Enables sending of the JITs intermediate representation for a specified
1934 method to the IdealGraphVisualizer tool.
1936 \fBMONO_VERBOSE_HWCAP\fR
1937 If set, makes the JIT output information about detected CPU features
1938 (such as SSE, CMOV, FCMOV, etc) to stdout.
1940 \fBMONO_CONSERVATIVE_HWCAP\fR
1941 If set, the JIT will not perform any hardware capability detection. This
1942 may be useful to pinpoint the cause of JIT issues. This is the default
1943 when Mono is built as an AOT cross compiler, so that the generated code
1944 will run on most hardware.
1946 If you want to use Valgrind, you will find the file `mono.supp'
1947 useful, it contains the suppressions for the GC which trigger
1948 incorrect warnings. Use it like this:
1950 valgrind --suppressions=mono.supp mono ...
1953 On some platforms, Mono can expose a set of DTrace probes (also known
1954 as user-land statically defined, USDT Probes).
1956 They are defined in the file `mono.d'.
1958 .B ves-init-begin, ves-init-end
1960 Begin and end of runtime initialization.
1962 .B method-compile-begin, method-compile-end
1964 Begin and end of method compilation.
1965 The probe arguments are class name, method name and signature,
1966 and in case of method-compile-end success or failure of compilation.
1970 Begin and end of Garbage Collection.
1972 To verify the availability of the probes, run:
1974 dtrace -P mono'$target' -l -c mono
1977 Mono's Ping implementation for detecting network reachability can
1978 create the ICMP packets itself without requiring the system ping
1979 command to do the work. If you want to enable this on Linux for
1980 non-root users, you need to give the Mono binary special permissions.
1982 As root, run this command:
1984 # setcap cap_net_raw=+ep /usr/bin/mono
1987 On Unix assemblies are loaded from the installation lib directory. If you set
1988 `prefix' to /usr, the assemblies will be located in /usr/lib. On
1989 Windows, the assemblies are loaded from the directory where mono and
1992 .B ~/.mono/aot-cache
1994 The directory for the ahead-of-time compiler demand creation
1995 assemblies are located.
1997 .B /etc/mono/config, ~/.mono/config
1999 Mono runtime configuration file. See the mono-config(5) manual page
2000 for more information.
2002 .B ~/.config/.mono/certs, /usr/share/.mono/certs
2004 Contains Mono certificate stores for users / machine. See the certmgr(1)
2005 manual page for more information on managing certificate stores and
2006 the mozroots(1) page for information on how to import the Mozilla root
2007 certificates into the Mono certificate store.
2009 .B ~/.mono/assemblies/ASSEMBLY/ASSEMBLY.config
2011 Files in this directory allow a user to customize the configuration
2012 for a given system assembly, the format is the one described in the
2013 mono-config(5) page.
2015 .B ~/.config/.mono/keypairs, /usr/share/.mono/keypairs
2017 Contains Mono cryptographic keypairs for users / machine. They can be
2018 accessed by using a CspParameters object with DSACryptoServiceProvider
2019 and RSACryptoServiceProvider classes.
2021 .B ~/.config/.isolatedstorage, ~/.local/share/.isolatedstorage, /usr/share/.isolatedstorage
2023 Contains Mono isolated storage for non-roaming users, roaming users and
2024 local machine. Isolated storage can be accessed using the classes from
2025 the System.IO.IsolatedStorage namespace.
2027 .B <assembly>.config
2029 Configuration information for individual assemblies is loaded by the
2030 runtime from side-by-side files with the .config files, see the
2031 http://www.mono-project.com/Config for more information.
2033 .B Web.config, web.config
2035 ASP.NET applications are configured through these files, the
2036 configuration is done on a per-directory basis. For more information
2037 on this subject see the http://www.mono-project.com/Config_system.web
2040 Mailing lists are listed at the
2041 http://www.mono-project.com/community/help/mailing-lists/
2043 http://www.mono-project.com
2046 \fBcertmgr\fR(1), \fBcert-sync\fR(1), \fBcsharp\fR(1),
2047 \fBgacutil\fR(1), \fBmcs\fR(1), \fBmonodis\fR(1),
2048 \fBmono-config\fR(5), \fBmono\-profilers\fR(1),
2049 \fBmprof\-report\fR(1), \fBpdb2mdb\fR(1), \fBxsp\fR(1),
2052 For more information on AOT:
2053 http://www.mono-project.com/docs/advanced/aot/
2055 For ASP.NET-related documentation, see the xsp(1) manual page