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 additionaly 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 override the built-in set of flags passed to the
219 LLVM optimizer. The list of possible flags that can be passed can be
220 obtained by calling the bundled
222 program that comes with Mono.
224 .I llvm-outfile=[filename]
225 Gives the path for the temporary LLVM bitcode file created during AOT.
227 Each AOT module will typically contain the code for inflated methods and wrappers that
228 are called by code in that module. In dedup mode, we identify and skip compiling all of those
229 methods. When using this mode with fullaot, dedup-include is required or these methods will
232 .I dedup-include=[filename]
233 In dedup-include mode, we are in the pass of compilation where we compile the methods
234 that we had previously skipped. All of them are emitted into the assembly that is passed
235 as this option. We consolidate the many duplicate skipped copies of the same method into one.
239 Print the architecture the AOT in this copy of Mono targets and quit.
242 Generates all required wrappers, so that it is possible to run --interpreter without
243 any code generation at runtime. This option only makes sense with \fBmscorlib.dll\fR.
247 mono_jit_set_aot_mode (MONO_AOT_MODE_INTERP);
252 Additional flags to pass to the C linker (if the current AOT mode calls for invoking it).
254 .I llvm-path=<PREFIX>
255 Same for the llvm tools 'opt' and 'llc'.
258 Instructs the AOT compiler to generate offline sequence points .msym files.
259 The generated .msym files will be stored into a subfolder of <PATH> named as the
263 Use the GNU style target triple <TRIPLE> to determine some code generation options, i.e.
264 --mtriple=armv7-linux-gnueabi will generate code that targets ARMv7. This is currently
265 only supported by the ARM backend. In LLVM mode, this triple is passed on to the LLVM
268 .I nimt-trampolines=[number]
269 When compiling in full aot mode, the IMT trampolines must be precreated
270 in the AOT image. You can add additional method trampolines with this argument.
273 .I ngsharedvt-trampolines=[number]
274 When compiling in full aot mode, the value type generic sharing trampolines must be precreated
275 in the AOT image. You can add additional method trampolines with this argument.
279 Instructs the AOT compiler to not output any debugging information.
282 This prevents the AOT compiler from generating a direct calls to a
283 method. The AOT compiler usually generates direct calls for certain
284 methods that do not require going through the PLT (for example,
285 methods that are known to not require a hook like a static
286 constructor) or call into simple internal calls.
288 .I nrgctx-trampolines=[number]
289 When compiling in full aot mode, the generic sharing trampolines must be precreated
290 in the AOT image. You can add additional method trampolines with this argument.
293 .I nrgctx-fetch-trampolines=[number]
294 When compiling in full aot mode, the generic sharing fetch trampolines must be precreated
295 in the AOT image. You can add additional method trampolines with this argument.
298 .I ntrampolines=[number]
299 When compiling in full aot mode, the method trampolines must be precreated
300 in the AOT image. You can add additional method trampolines with this argument.
303 .I outfile=[filename]
304 Instructs the AOT compiler to save the output to the specified file.
306 .I print-skipped-methods
307 If the AOT compiler cannot compile a method for any reason, enabling this flag
308 will output the skipped methods to the console.
311 Specify a file to use for profile-guided optimization. See the \fBAOT profiler\fR sub-section. To specify multiple files, include the
313 option multiple times.
316 AOT *only* the methods described in the files specified with the
318 option. See the \fBAOT profiler\fR sub-section.
320 .I readonly-value=namespace.typename.fieldname=type/value
321 Override the value of a static readonly field. Usually, during JIT
322 compilation, the static constructor is ran eagerly, so the value of
323 a static readonly field is known at compilation time and the compiler
324 can do a number of optimizations based on it. During AOT, instead, the static
325 constructor can't be ran, so this option can be used to set the value of such
326 a field and enable the same set of optimizations.
327 Type can be any of i1, i2, i4 for integers of the respective sizes (in bytes).
328 Note that signed/unsigned numbers do not matter here, just the storage size.
329 This option can be specified multiple times and it doesn't prevent the static
330 constructor for the type defining the field to execute with the usual rules
331 at runtime (hence possibly computing a different value for the field).
333 .I save-temps,keep-temps
334 Instructs the AOT compiler to keep temporary files.
337 This instructs the compiler to generate sequence point checks that
338 allow Mono's soft debugger to debug applications even on systems where
339 it is not possible to set breakpoints or to single step (certain
340 hardware configurations like the cell phones and video gaming
344 Create an ELF object file (.o) or .s file which can be statically linked into an
345 executable when embedding the mono runtime. When this option is used, the object file
346 needs to be registered with the embedded runtime using the mono_aot_register_module
347 function which takes as its argument the mono_aot_module_<ASSEMBLY NAME>_info global
348 symbol from the object file:
351 extern void *mono_aot_module_hello_info;
353 mono_aot_register_module (mono_aot_module_hello_info);
358 Print various stats collected during AOT compilation.
361 Explicitly specify path to store temporary files created during AOT compilation.
364 This is an experimental option for the AOT compiler to use multiple threads
365 when compiling the methods.
367 .I tool-prefix=<PREFIX>
368 Prepends <PREFIX> to the name of tools ran by the AOT compiler, i.e. 'as'/'ld'. For
369 example, --tool=prefix=arm-linux-gnueabi- will make the AOT compiler run
370 'arm-linux-gnueabi-as' instead of 'as'.
373 Prints additional information about type loading failures.
375 .I write-symbols,no-write-symbols
376 Instructs the AOT compiler to emit (or not emit) debug symbol information.
378 For more information about AOT, see: http://www.mono-project.com/docs/advanced/aot/
381 \fB--aot-path=PATH\fR
382 List of additional directories to search for AOT images.
384 \fB--apply-bindings=FILE\fR
385 Apply the assembly bindings from the specified configuration file when running
386 the AOT compiler. This is useful when compiling an auxiliary assembly that is
387 referenced by a main assembly that provides a configuration file. For example,
388 if app.exe uses lib.dll then in order to make the assembly bindings from
389 app.exe.config available when compiling lib.dll ahead of time, use:
391 mono --apply-bindings=app.exe.config --aot lib.dll
394 \fB--assembly-loader=MODE\fR
395 If mode is \fBstrict\fR, Mono will check that the public key token, culture and version
396 of a candidate assembly matches the requested strong name. If mode is \fBlegacy\fR, as
397 long as the name matches, the candidate will be allowed. \fBstrict\fR is the behavior
398 consistent with .NET Framework but may break some existing mono-based applications.
399 The default is \fBlegacy\fR.
401 \fB--attach=[options]\fR
402 Currently the only option supported by this command line argument is
403 \fBdisable\fR which disables the attach functionality.
405 \fB--config filename\fR
406 Load the specified configuration file instead of the default one(s).
407 The default files are /etc/mono/config and ~/.mono/config or the file
408 specified in the MONO_CONFIG environment variable, if set. See the
409 mono-config(5) man page for details on the format of this file.
411 \fB--debugger-agent=[options]\fR
412 This instructs the Mono runtime to
413 start a debugging agent inside the Mono runtime and connect it to a
414 client user interface will control the Mono process.
415 This option is typically used by IDEs, like the MonoDevelop or Visual Studio IDEs.
417 The configuration is specified using one of more of the following options:
423 Use this option to specify the IP address where your debugger client is
428 Specifies the diagnostics log level for
432 Used to specify the file where the log will be stored, it defaults to
436 Defaults to no, with the default option Mono will actively connect to the
437 host/port configured with the \fBaddress\fR option. If you set it to 'y', it
438 instructs the Mono runtime to start debugging in server mode, where Mono
439 actively waits for the debugger front end to connect to the Mono process.
440 Mono will print out to stdout the IP address and port where it is listening.
443 If set to yes, Mono will call \fBsetpgid(0, 0)\fR on startup, if that function
444 is available on the system. This is useful for ensuring that signals delivered
445 to a process that is executing the debuggee are not propagated to the debuggee,
446 e.g. when Ctrl-C sends \fBSIGINT\fR to the \fBsdb\fR tool.
449 Defaults to yes, with the default option Mono will suspend the vm on startup
450 until it connects successfully to a debugger front end. If you set it to 'n', in
451 conjunction with \fBserver=y\fR, it instructs the Mono runtime to run as normal,
452 while caching metadata to send to the debugger front end on connection..
454 .I transport=transport_name
456 This is used to specify the transport that the debugger will use to
457 communicate. It must be specified and currently requires this to
463 Configures the virtual machine to be better suited for desktop
464 applications. Currently this sets the GC system to avoid expanding
465 the heap as much as possible at the expense of slowing down garbage
469 This flag instructs the Mono runtime to not
470 generate any code at runtime and depend exclusively on the code
471 generated from using mono --aot=full previously. This is useful for
472 platforms that do not permit dynamic code generation, or if you need
473 to run assemblies that have been stripped of IL (for example using
476 Notice that this feature will abort execution at runtime if a codepath
477 in your program, or Mono's class libraries attempts to generate code
478 dynamically. You should test your software upfront and make sure that
479 you do not use any dynamic features.
481 \fB--full-aot-interp\fR
482 Same as --full-aot with fallback to the interpreter.
484 \fB--gc=boehm\fR, \fB--gc=sgen\fR
485 Selects the Garbage Collector engine for Mono to use, Boehm or SGen.
486 Currently this merely ensures that you are running either the
487 \fImono\fR or \fImono-sgen\fR commands. This flag can be set in the
488 \fBMONO_ENV_OPTIONS\fR environment variable to force all of your child
489 processes to use one particular kind of GC with the Mono runtime.
491 \fB--gc-debug=[options]\fR
492 Command line equivalent of the \fBMONO_GC_DEBUG\fR environment variable.
494 \fB--gc-params=[options]\fR
495 Command line equivalent of the \fBMONO_GC_PARAMS\fR environment variable.
497 \fB--arch=32\fR, \fB--arch=64\fR
498 (Mac OS X only): Selects the bitness of the Mono binary used, if
499 available. If the binary used is already for the selected bitness, nothing
500 changes. If not, the execution switches to a binary with the selected
501 bitness suffix installed side by side (for example, '/bin/mono --arch=64'
502 will switch to '/bin/mono64' iff '/bin/mono' is a 32-bit build).
504 \fB--help\fR, \fB-h\fR
505 Displays usage instructions.
508 The Mono runtime will use its interpreter to execute a given assembly.
509 The interpreter is usually slower than the JIT, but it can be useful on
510 platforms where code generation at runtime is not allowed.
513 This flag allows the Mono runtime to run assemblies
514 that have been stripped of IL, for example using mono-cil-strip. For this to
515 work, the assembly must have been AOT compiled with --aot=hybrid.
517 This flag is similar to --full-aot, but it does not disable the JIT. This means
518 you can use dynamic features such as System.Reflection.Emit.
521 If the Mono runtime has been compiled with LLVM support (not available
522 in all configurations), Mono will use the LLVM optimization and code
523 generation engine to JIT or AOT compile.
525 For more information, consult: http://www.mono-project.com/docs/advanced/mono-llvm/
528 When using a Mono that has been compiled with LLVM support, it forces
529 Mono to fallback to its JIT engine and not use the LLVM backend.
531 \fB--optimize=MODE\fR, \fB-O=MODE\fR
532 MODE is a comma separated list of optimizations. They also allow
533 optimizations to be turned off by prefixing the optimization name with
536 In general, Mono has been tuned to use the default set of flags,
537 before using these flags for a deployment setting, you might want to
538 actually measure the benefits of using them.
540 The following optimization flags are implemented in the core engine:
542 abcrem Array bound checks removal
543 all Turn on all optimizations
544 aot Usage of Ahead Of Time compiled code
545 branch Branch optimizations
546 cfold Constant folding
547 cmov Conditional moves [arch-dependency]
548 deadce Dead code elimination
549 consprop Constant propagation
550 copyprop Copy propagation
551 fcmov Fast x86 FP compares [arch-dependency]
552 float32 Perform 32-bit float arithmetic using 32-bit operations
553 gshared Enable generic code sharing.
554 inline Inline method calls
555 intrins Intrinsic method implementations
556 linears Linear scan global reg allocation
557 leaf Leaf procedures optimizations
558 loop Loop related optimizations
559 peephole Peephole postpass
560 precomp Precompile all methods before executing Main
561 sched Instruction scheduling
562 shared Emit per-domain code
563 sse2 SSE2 instructions on x86 [arch-dependency]
564 tailc Tail recursion and tail calls
567 For example, to enable all the optimization but dead code
568 elimination and inlining, you can use:
570 -O=all,-deadce,-inline
573 The flags that are flagged with [arch-dependency] indicate that the
574 given option if used in combination with Ahead of Time compilation
575 (--aot flag) would produce pre-compiled code that will depend on the
576 current CPU and might not be safely moved to another computer.
580 The following optimizations are supported
583 Requests that the runtime performn 32-bit floating point operations
584 using only 32-bits. By default the Mono runtime tries to use the
585 highest precision available for floating point operations, but while
586 this might render better results, the code might run slower. This
587 options also affects the code generated by the LLVM backend.
590 Controls whether the runtime should attempt to inline (the default),
591 or not inline methods invocations
594 \fB--response=FILE\fR
595 Provides a response file, this instructs the Mono command to read
596 other command line options from the specified file, as if the
597 options had been specified on the command line. Useful when you have
598 very long command lines.
600 \fB--runtime=VERSION\fR
601 Mono supports different runtime versions. The version used depends on the program
602 that is being run or on its configuration file (named program.exe.config). This option
603 can be used to override such autodetection, by forcing a different runtime version
604 to be used. Note that this should only be used to select a later compatible runtime
605 version than the one the program was compiled against. A typical usage is for
606 running a 1.1 program on a 2.0 version:
608 mono --runtime=v2.0.50727 program.exe
611 \fB--security\fR, \fB--security=mode\fR
612 Activate the security manager, a currently experimental feature in
613 Mono and it is OFF by default. The new code verifier can be enabled
614 with this option as well.
618 Using security without parameters is equivalent as calling it with the
621 The following modes are supported:
624 Enables the core-clr security system, typically used for
625 Moonlight/Silverlight applications. It provides a much simpler
626 security system than CAS, see http://www.mono-project.com/docs/web/moonlight/
627 for more details and links to the descriptions of this new system.
630 Enables the new verifier and performs basic verification for code
631 validity. In this mode, unsafe code and P/Invoke are allowed. This
632 mode provides a better safety guarantee but it is still possible
633 for managed code to crash Mono.
636 Enables the new verifier and performs full verification of the code
637 being executed. It only allows verifiable code to be executed.
638 Unsafe code is not allowed but P/Invoke is. This mode should
639 not allow managed code to crash mono. The verification is not as
640 strict as ECMA 335 standard in order to stay compatible with the MS
643 The security system acts on user code: code contained in mscorlib or
644 the global assembly cache is always trusted.
649 Configures the virtual machine to be better suited for server
650 operations (currently, allows a heavier threadpool initialization).
653 Verifies mscorlib and assemblies in the global
654 assembly cache for valid IL, and all user code for IL
657 This is different from \fB--security\fR's verifiable
658 or validil in that these options only check user code and skip
659 mscorlib and assemblies located on the global assembly cache.
661 \fB-V\fR, \fB--version\fR
662 Prints JIT version information (system configuration, release number
663 and branch names if available).
666 .SH DEVELOPMENT OPTIONS
667 The following options are used to help when developing a JITed application.
669 \fB--debug\fR, \fB--debug=OPTIONS\fR
670 Turns on the debugging mode in the runtime. If an assembly was
671 compiled with debugging information, it will produce line number
672 information for stack traces.
676 The optional OPTIONS argument is a comma separated list of debugging
677 options. These options are turned off by default since they generate
678 much larger and slower code at runtime.
680 The following options are supported:
683 Produces a detailed error when throwing a InvalidCastException. This
684 option needs to be enabled as this generates more verbose code at
688 Disable some JIT optimizations which are usually only disabled when
689 running inside the debugger. This can be helpful if you want to attach
690 to the running process with mdb.
693 Generate and register debugging information with gdb. This is only supported on some
694 platforms, and only when using gdb 7.0 or later.
698 \fB\-\-profile\fR[=\fIprofiler\fR[:\fIprofiler_args\fR]]\fR
699 Loads a profiler module with the given arguments. For more information,
700 see the \fBPROFILING\fR section.
702 This option can be used multiple times; each time will load an additional
705 \fB--trace[=expression]\fR
706 Shows method names as they are invoked. By default all methods are
709 The trace can be customized to include or exclude methods, classes or
710 assemblies. A trace expression is a comma separated list of targets,
711 each target can be prefixed with a minus sign to turn off a particular
712 target. The words `program', `all' and `disabled' have special
713 meaning. `program' refers to the main program being executed, and
714 `all' means all the method calls.
716 The `disabled' option is used to start up with tracing disabled. It
717 can be enabled at a later point in time in the program by sending the
718 SIGUSR2 signal to the runtime.
720 Assemblies are specified by their name, for example, to trace all
721 calls in the System assembly, use:
724 mono --trace=System app.exe
727 Classes are specified with the T: prefix. For example, to trace all
728 calls to the System.String class, use:
731 mono --trace=T:System.String app.exe
734 And individual methods are referenced with the M: prefix, and the
735 standard method notation:
738 mono --trace=M:System.Console:WriteLine app.exe
741 Exceptions can also be traced, it will cause a stack trace to be
742 printed every time an exception of the specified type is thrown.
743 The exception type can be specified with or without the namespace,
744 and to trace all exceptions, specify 'all' as the type name.
747 mono --trace=E:System.Exception app.exe
750 As previously noted, various rules can be specified at once:
753 mono --trace=T:System.String,T:System.Random app.exe
756 You can exclude pieces, the next example traces calls to
757 System.String except for the System.String:Concat method.
760 mono --trace=T:System.String,-M:System.String:Concat
763 You can trace managed to unmanaged transitions using
764 the wrapper qualifier:
767 mono --trace=wrapper app.exe
770 Finally, namespaces can be specified using the N: prefix:
773 mono --trace=N:System.Xml
777 \fB--no-x86-stack-align\fR
778 Don't align stack frames on the x86 architecture. By default, Mono
779 aligns stack frames to 16 bytes on x86, so that local floating point
780 and SIMD variables can be properly aligned. This option turns off the
781 alignment, which usually saves one instruction per call, but might
782 result in significantly lower floating point and SIMD performance.
785 Generate a JIT method map in a /tmp/perf-PID.map file. This file is then
786 used, for example, by the perf tool included in recent Linux kernels.
787 Each line in the file has:
790 HEXADDR HEXSIZE methodname
793 Currently this option is only supported on Linux.
794 .SH JIT MAINTAINER OPTIONS
795 The maintainer options are only used by those developing the runtime
796 itself, and not typically of interest to runtime users or developers.
798 \fB--bisect=optimization:filename\fR
799 This flag is used by the automatic optimization bug bisector. It
800 takes an optimization flag and a filename of a file containing a list
801 of full method names, one per line. When it compiles one of the
802 methods in the file it will use the optimization given, in addition to
803 the optimizations that are otherwise enabled. Note that if the
804 optimization is enabled by default, you should disable it with `-O`,
805 otherwise it will just apply to every method, whether it's in the file
809 Inserts a breakpoint before the method whose name is `method'
810 (namespace.class:methodname). Use `Main' as method name to insert a
811 breakpoint on the application's main method. You can use it also with
812 generics, for example "System.Collections.Generic.Queue`1:Peek"
815 Inserts a breakpoint on exceptions. This allows you to debug your
816 application with a native debugger when an exception is thrown.
819 This compiles a method (namespace.name:methodname), this is used for
820 testing the compiler performance or to examine the output of the code
824 Compiles all the methods in an assembly. This is used to test the
825 compiler performance or to examine the output of the code generator
827 \fB--graph=TYPE METHOD\fR
828 This generates a postscript file with a graph with the details about
829 the specified method (namespace.name:methodname). This requires `dot'
830 and ghostview to be installed (it expects Ghostview to be called
833 The following graphs are available:
835 cfg Control Flow Graph (CFG)
837 code CFG showing code
838 ssa CFG showing code after SSA translation
839 optcode CFG showing code after IR optimizations
842 Some graphs will only be available if certain optimizations are turned
846 Instruct the runtime on the number of times that the method specified
847 by --compile (or all the methods if --compileall is used) to be
848 compiled. This is used for testing the code generator performance.
851 Displays information about the work done by the runtime during the
852 execution of an application.
854 \fB--wapi=hps|semdel\fR
855 Perform maintenance of the process shared data.
857 semdel will delete the global semaphore.
859 hps will list the currently used handles.
861 \fB-v\fR, \fB--verbose\fR
862 Increases the verbosity level, each time it is listed, increases the
863 verbosity level to include more information (including, for example,
864 a disassembly of the native code produced, code selector info etc.).
866 The Mono runtime allows external processes to attach to a running
867 process and load assemblies into the running program. To attach to
868 the process, a special protocol is implemented in the Mono.Management
871 With this support it is possible to load assemblies that have an entry
872 point (they are created with -target:exe or -target:winexe) to be
873 loaded and executed in the Mono process.
875 The code is loaded into the root domain, and it starts execution on
876 the special runtime attach thread. The attached program should
877 create its own threads and return after invocation.
879 This support allows for example debugging applications by having the
880 csharp shell attach to running processes.
882 The Mono runtime includes a profiler API that dynamically loaded
883 profiler modules and embedders can use to collect performance-related
884 data about an application. Profiler modules are loaded by passing the
885 \fB\-\-profile\fR command line argument to the Mono runtime.
887 Mono ships with a few profiler modules, of which the \fBlog\fR profiler
888 is the most feature-rich. It is also the default profiler if the
889 \fIprofiler\fR argument is not given, or if \fBdefault\fR is given.
890 It is possible to write your own profiler modules; see the
891 \fBCustom profilers\fR sub-section.
893 The log profiler can be used to collect a lot of information about
894 a program running in the Mono runtime. This data can be used (both
895 while the process is running and later) to do analyses of the
896 program behavior, determine resource usage, performance issues or
897 even look for particular execution patterns.
899 This is accomplished by logging the events provided by the Mono
900 runtime through the profiler API and periodically writing them to a
901 file which can later be inspected with the \fBmprof\-report\fR(1)
904 More information about how to use the log profiler is available on
905 the \fBmono\-profilers\fR(1) page, under the \fBLOG PROFILER\fR
906 section, as well as the \fBmprof\-report\fR(1) page.
907 .SS Coverage profiler
908 The code coverage profiler can instrument a program to help determine
909 which classes, methods, code paths, etc are actually executed. This
910 is most useful when running a test suite to determine whether the
911 tests actually cover the code they're expected to.
913 More information about how to use the coverage profiler is available
914 on the \fBmono\-profilers\fR(1) page, under the \fBCOVERAGE
917 The AOT profiler can help improve startup performance by logging
918 which generic instantiations are used by a program, which the AOT
919 compiler can then use to compile those instantiations ahead of time
920 so that they won't have to be JIT compiled at startup.
922 More information about how to use the AOT profiler is available on
923 the \fBmono\-profilers\fR(1) page, under the \fBAOT PROFILER\fR
926 Custom profiler modules can be loaded in exactly the same way as the
927 standard modules that ship with Mono. They can also access the same
928 profiler API to gather all kinds of information about the code being
931 For example, to use a third-party profiler called \fBcustom\fR, you
932 would load it like this:
936 mono --profile=custom program.exe
940 You could also pass arguments to it:
944 mono --profile=custom:arg1,arg2=arg3 program.exe
948 In the above example, Mono will load the profiler from the shared
949 library called \fIlibmono\-profiler\-custom.so\fR (name varies based
950 on platform, e.g., \fIlibmono\-profiler\-custom.dylib\fR on OS X).
951 This profiler module must be on your dynamic linker library path
952 (\fBLD_LIBRARY_PATH\fR on most systems, \fBDYLD_LIBRARY_PATH\fR on
955 For a sample of how to write your own custom profiler, look at the
956 \fIsamples/profiler/sample.c\fR file in the Mono source tree.
958 To debug managed applications, you can use the
960 command, a command line debugger.
962 It is possible to obtain a stack trace of all the active threads in
963 Mono by sending the QUIT signal to Mono, you can do this from the
964 command line, like this:
970 Where pid is the Process ID of the Mono process you want to examine.
971 The process will continue running afterwards, but its state is not
975 this is a last-resort mechanism for debugging applications and should
976 not be used to monitor or probe a production application. The
977 integrity of the runtime after sending this signal is not guaranteed
978 and the application might crash or terminate at any given point
981 The \fB--debug=casts\fR option can be used to get more detailed
982 information for Invalid Cast operations, it will provide information
983 about the types involved.
985 You can use the MONO_LOG_LEVEL and MONO_LOG_MASK environment variables
986 to get verbose debugging output about the execution of your
987 application within Mono.
991 environment variable if set, the logging level is changed to the set
992 value. Possible values are "error", "critical", "warning", "message",
993 "info", "debug". The default value is "error". Messages with a logging
994 level greater then or equal to the log level will be printed to
997 Use "info" to track the dynamic loading of assemblies.
1002 environment variable to limit the extent of the messages you get:
1003 If set, the log mask is changed to the set value. Possible values are
1004 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1005 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1006 "security" (e.g. Moonlight CoreCLR support), "threadpool" (thread pool generic),
1007 "io-selector" (async socket operations), "io-layer" (I/O layer - processes, files,
1008 sockets, events, semaphores, mutexes and handles), "io-layer-process",
1009 "io-layer-file", "io-layer-socket", "io-layer-event", "io-layer-semaphore",
1010 "io-layer-mutex", "io-layer-handle" and "all".
1011 The default value is "all". Changing the mask value allows you to display only
1012 messages for a certain component. You can use multiple masks by comma
1013 separating them. For example to see config file messages and assembly loader
1014 messages set you mask to "asm,cfg".
1016 The following is a common use to track down problems with P/Invoke:
1019 $ MONO_LOG_LEVEL="debug" MONO_LOG_MASK="dll" mono glue.exe
1023 .SH DEBUGGING WITH LLDB
1024 If you are using LLDB, you can use the
1026 script to print some internal data structures with it. To use this,
1031 command script import $PREFIX/lib/mono/lldb/mono.py
1034 Where $PREFIX is the prefix value that you used when you configured
1035 Mono (typically /usr).
1037 Once this is done, then you can inspect some Mono Runtime data structures,
1042 (MonoMethod *) $0 = 0x05026ac0 [mscorlib]System.OutOfMemoryException:.ctor()
1045 Mono's XML serialization engine by default will use a reflection-based
1046 approach to serialize which might be slow for continuous processing
1047 (web service applications). The serialization engine will determine
1048 when a class must use a hand-tuned serializer based on a few
1049 parameters and if needed it will produce a customized C# serializer
1050 for your types at runtime. This customized serializer then gets
1051 dynamically loaded into your application.
1053 You can control this with the MONO_XMLSERIALIZER_THS environment
1056 The possible values are
1058 to disable the use of a C# customized
1059 serializer, or an integer that is the minimum number of uses before
1060 the runtime will produce a custom serializer (0 will produce a
1061 custom serializer on the first access, 50 will produce a serializer on
1062 the 50th use). Mono will fallback to an interpreted serializer if the
1063 serializer generation somehow fails. This behavior can be disabled
1064 by setting the option
1066 (for example: MONO_XMLSERIALIZER_THS=0,nofallback).
1067 .SH ENVIRONMENT VARIABLES
1070 Turns off the garbage collection in Mono. This should be only used
1071 for debugging purposes
1074 (Also \fBhttp_proxy\fR) If set, web requests using the Mono
1075 Class Library will be automatically proxied through the given URL.
1076 Not supported on Windows, Mac OS, iOS or Android. See also \fBNO_PROXY\fR.
1079 When Mono is compiled with LLVM support, this instructs the runtime to
1080 stop using LLVM after the specified number of methods are JITed.
1081 This is a tool used in diagnostics to help isolate problems in the
1082 code generation backend. For example \fBLLVM_COUNT=10\fR would only
1083 compile 10 methods with LLVM and then switch to the Mono JIT engine.
1084 \fBLLVM_COUNT=0\fR would disable the LLVM engine altogether.
1086 \fBMONO_ASPNET_INHIBIT_SETTINGSMAP\fR
1087 Mono contains a feature which allows modifying settings in the .config files shipped
1088 with Mono by using config section mappers. The mappers and the mapping rules are
1089 defined in the $prefix/etc/mono/2.0/settings.map file and, optionally, in the
1090 settings.map file found in the top-level directory of your ASP.NET application.
1091 Both files are read by System.Web on application startup, if they are found at the
1092 above locations. If you don't want the mapping to be performed you can set this
1093 variable in your environment before starting the application and no action will
1096 \fBMONO_ASPNET_WEBCONFIG_CACHESIZE\fR
1097 Mono has a cache of ConfigSection objects for speeding up WebConfigurationManager
1098 queries. Its default size is 100 items, and when more items are needed, cache
1099 evictions start happening. If evictions are too frequent this could impose
1100 unnecessary overhead, which could be avoided by using this environment variable
1101 to set up a higher cache size (or to lower memory requirements by decreasing it).
1103 \fBMONO_CAIRO_DEBUG_DISPOSE\fR
1104 If set, causes Mono.Cairo to collect stack traces when objects are allocated,
1105 so that the finalization/Dispose warnings include information about the
1109 If set, this variable overrides the default system configuration directory
1110 ($PREFIX/etc). It's used to locate machine.config file.
1113 Sets the style of COM interop. If the value of this variable is "MS"
1114 Mono will use string marhsalling routines from the liboleaut32 for the
1115 BSTR type library, any other values will use the mono-builtin BSTR
1119 If set, this variable overrides the default runtime configuration file
1120 ($PREFIX/etc/mono/config). The --config command line options overrides the
1121 environment variable.
1124 Override the automatic cpu detection mechanism. Currently used only on arm.
1125 The format of the value is as follows:
1131 where V is the architecture number 4, 5, 6, 7 and the options can be currently be
1132 "thumb" or "thumb2". Example:
1135 MONO_CPU_ARCH="armv4 thumb" mono ...
1139 \fBMONO_ARM_FORCE_SOFT_FLOAT\fR
1140 When Mono is built with a soft float fallback on ARM and this variable is set to
1141 "1", Mono will always emit soft float code, even if a VFP unit is
1144 \fBMONO_DARWIN_USE_KQUEUE_FSW\fR
1145 Fall back on the kqueue FileSystemWatcher implementation in Darwin. The default is the FSEvent implementation.
1147 \fBMONO_DARWIN_WATCHER_MAXFDS\fR
1148 This is a debugging aid used to force limits on the kqueue FileSystemWatcher
1149 implementation in Darwin. There is no limit by default.
1151 \fBMONO_DISABLE_MANAGED_COLLATION\fR
1152 If this environment variable is `yes', the runtime uses unmanaged
1153 collation (which actually means no culture-sensitive collation). It
1154 internally disables managed collation functionality invoked via the
1155 members of System.Globalization.CompareInfo class. Collation is
1158 \fBMONO_DISABLE_SHARED_AREA\fR
1159 Unix only: If set, disable usage of shared memory for exposing
1160 performance counters. This means it will not be possible to both
1161 externally read performance counters from this processes or read
1162 those of external processes.
1165 When set, enables the use of a fully managed DNS resolver instead of the
1166 regular libc functions. This resolver performs much better when multiple
1167 queries are run in parallel.
1169 Note that /etc/nsswitch.conf will be ignored.
1171 \fBMONO_EGD_SOCKET\fR
1172 For platforms that do not otherwise have a way of obtaining random bytes
1173 this can be set to the name of a file system socket on which an egd or
1174 prngd daemon is listening.
1176 \fBMONO_ENABLE_AIO\fR
1177 If set, tells mono to attempt using native asynchronous I/O services. If not
1178 set, a default select/poll implementation is used. Currently epoll and kqueue
1181 \fBMONO_ENABLE_COOP_SUSPEND\fR
1182 This makes the Mono runtime and the SGen garbage collector run in cooperative
1183 mode as opposed to run on preemptive mode. Preemptive mode is the mode
1184 that Mono has used historically, going back to the Boehm days, where the
1185 garbage collector would run at any point and suspend execution of all
1186 threads as required to perform a garbage collection. The cooperative mode
1187 on the other hand requires the cooperation of all threads to stop at a
1188 safe point. This makes for an easier to debug garbage collector. As
1189 of Mono 4.3.0 it is a work in progress, and while it works, it has not
1190 been used extensively. This option enabled the feature and allows us to
1191 find spots that need to be tuned for this mode of operation. Alternatively,
1192 this mode can be enabled at compile time by using the --enable-cooperative-suspend
1193 flag when calling configure.
1195 \fBMONO_ENV_OPTIONS\fR
1196 This environment variable allows you to pass command line arguments to
1197 a Mono process through the environment. This is useful for example
1198 to force all of your Mono processes to use LLVM or SGEN without having
1199 to modify any launch scripts.
1201 \fBMONO_SDB_ENV_OPTIONS\fR
1202 Used to pass extra options to the debugger agent in the runtime, as they were passed
1203 using --debugger-agent=.
1205 \fBMONO_EVENTLOG_TYPE\fR
1206 Sets the type of event log provider to use (for System.Diagnostics.EventLog).
1208 Possible values are:
1213 Persists event logs and entries to the local file system.
1215 The directory in which to persist the event logs, event sources and entries
1216 can be specified as part of the value.
1218 If the path is not explicitly set, it defaults to "/var/lib/mono/eventlog"
1219 on unix and "%APPDATA%\mono\eventlog" on Windows.
1224 Uses the native win32 API to write events and registers event logs and
1225 event sources in the registry. This is only available on Windows.
1227 On Unix, the directory permission for individual event log and event source
1228 directories is set to 777 (with +t bit) allowing everyone to read and write
1229 event log entries while only allowing entries to be deleted by the user(s)
1234 Silently discards any events.
1237 The default is "null" on Unix (and versions of Windows before NT), and
1238 "win32" on Windows NT (and higher).
1241 \fBMONO_EXTERNAL_ENCODINGS\fR
1242 If set, contains a colon-separated list of text encodings to try when
1243 turning externally-generated text (e.g. command-line arguments or
1244 filenames) into Unicode. The encoding names come from the list
1245 provided by iconv, and the special case "default_locale" which refers
1246 to the current locale's default encoding.
1248 When reading externally-generated text strings UTF-8 is tried first,
1249 and then this list is tried in order with the first successful
1250 conversion ending the search. When writing external text (e.g. new
1251 filenames or arguments to new processes) the first item in this list
1252 is used, or UTF-8 if the environment variable is not set.
1254 The problem with using MONO_EXTERNAL_ENCODINGS to process your
1255 files is that it results in a problem: although its possible to get
1256 the right file name it is not necessarily possible to open the file.
1257 In general if you have problems with encodings in your filenames you
1258 should use the "convmv" program.
1260 \fBMONO_GC_PARAMS\fR
1261 When using Mono with the SGen garbage collector this variable controls
1262 several parameters of the collector. The variable's value is a comma
1263 separated list of words.
1267 \fBmax-heap-size=\fIsize\fR
1268 Sets the maximum size of the heap. The size is specified in bytes and must
1269 be a power of two. The suffixes `k', `m' and `g' can be used to
1270 specify kilo-, mega- and gigabytes, respectively. The limit is the sum
1271 of the nursery, major heap and large object heap. Once the limit is reached
1272 the application will receive OutOfMemoryExceptions when trying to allocate.
1273 Not the full extent of memory set in max-heap-size could be available to
1274 satisfy a single allocation due to internal fragmentation. By default heap
1275 limits is disabled and the GC will try to use all available memory.
1277 \fBnursery-size=\fIsize\fR
1278 Sets the size of the nursery. The size is specified in bytes and must
1279 be a power of two. The suffixes `k', `m' and `g' can be used to
1280 specify kilo-, mega- and gigabytes, respectively. The nursery is the
1281 first generation (of two). A larger nursery will usually speed up the
1282 program but will obviously use more memory. The default nursery size
1285 \fBmajor=\fIcollector\fR
1286 Specifies which major collector to use.
1287 Options are `marksweep' for the Mark&Sweep collector, `marksweep-conc'
1288 for concurrent Mark&Sweep and `marksweep-conc-par' for parallel and
1289 concurrent Mark&Sweep. The concurrent Mark&Sweep collector is the default.
1291 \fBmode=balanced|throughput|pause\fR[:\fImax-pause\fR]
1292 Specifies what should be the garbage collector's target. The `throughput'
1293 mode aims to reduce time spent in the garbage collector and improve
1294 application speed, the `pause' mode aims to keep pause times to a minimum
1295 and it receives the argument \fImax-pause\fR which specifies the maximum
1296 pause time in milliseconds that is acceptable and the `balanced' mode
1297 which is a general purpose optimal mode.
1299 \fBsoft-heap-limit=\fIsize\fR
1300 Once the heap size gets larger than this size, ignore what the default
1301 major collection trigger metric says and only allow four nursery size's
1302 of major heap growth between major collections.
1304 \fBevacuation-threshold=\fIthreshold\fR
1305 Sets the evacuation threshold in percent. This option is only available
1306 on the Mark&Sweep major collectors. The value must be an
1307 integer in the range 0 to 100. The default is 66. If the sweep phase of
1308 the collection finds that the occupancy of a specific heap block type is
1309 less than this percentage, it will do a copying collection for that block
1310 type in the next major collection, thereby restoring occupancy to close
1311 to 100 percent. A value of 0 turns evacuation off.
1313 \fB(no-)lazy-sweep\fR
1314 Enables or disables lazy sweep for the Mark&Sweep collector. If
1315 enabled, the sweeping of individual major heap blocks is done
1316 piecemeal whenever the need arises, typically during nursery
1317 collections. Lazy sweeping is enabled by default.
1319 \fB(no-)concurrent-sweep\fR
1320 Enables or disables concurrent sweep for the Mark&Sweep collector. If
1321 enabled, the iteration of all major blocks to determine which ones can
1322 be freed and which ones have to be kept and swept, is done
1323 concurrently with the running program. Concurrent sweeping is enabled
1326 \fBstack-mark=\fImark-mode\fR
1327 Specifies how application threads should be scanned. Options are
1328 `precise` and `conservative`. Precise marking allow the collector
1329 to know what values on stack are references and what are not.
1330 Conservative marking threats all values as potentially references
1331 and leave them untouched. Precise marking reduces floating garbage
1332 and can speed up nursery collection and allocation rate, it has
1333 the downside of requiring a significant extra memory per compiled
1334 method. The right option, unfortunately, requires experimentation.
1336 \fBsave-target-ratio=\fIratio\fR
1337 Specifies the target save ratio for the major collector. The collector
1338 lets a given amount of memory to be promoted from the nursery due to
1339 minor collections before it triggers a major collection. This amount
1340 is based on how much memory it expects to free. It is represented as
1341 a ratio of the size of the heap after a major collection.
1342 Valid values are between 0.1 and 2.0. The default is 0.5.
1343 Smaller values will keep the major heap size smaller but will trigger
1344 more major collections. Likewise, bigger values will use more memory
1345 and result in less frequent major collections.
1346 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1348 \fBdefault-allowance-ratio=\fIratio\fR
1349 Specifies the default allocation allowance when the calculated size
1350 is too small. The allocation allowance is how much memory the collector
1351 let be promoted before triggered a major collection.
1352 It is a ratio of the nursery size.
1353 Valid values are between 1.0 and 10.0. The default is 4.0.
1354 Smaller values lead to smaller heaps and more frequent major collections.
1355 Likewise, bigger values will allow the heap to grow faster but use
1356 more memory when it reaches a stable size.
1357 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1359 \fBminor=\fIminor-collector\fR
1360 Specifies which minor collector to use. Options are `simple' which
1361 promotes all objects from the nursery directly to the old generation,
1362 `simple-par' which has same promotion behavior as `simple' but using
1363 multiple workers and `split' which lets objects stay longer on the nursery
1366 \fBalloc-ratio=\fIratio\fR
1367 Specifies the ratio of memory from the nursery to be use by the alloc space.
1368 This only can only be used with the split minor collector.
1369 Valid values are integers between 1 and 100. Default is 60.
1371 \fBpromotion-age=\fIage\fR
1372 Specifies the required age of an object must reach inside the nursery before
1373 been promoted to the old generation. This only can only be used with the
1374 split minor collector.
1375 Valid values are integers between 1 and 14. Default is 2.
1377 \fB(no-)cementing\fR
1378 Enables or disables cementing. This can dramatically shorten nursery
1379 collection times on some benchmarks where pinned objects are referred
1380 to from the major heap.
1382 \fBallow-synchronous-major\fR
1383 This forbids the major collector from performing synchronous major collections.
1384 The major collector might want to do a synchronous collection due to excessive
1385 fragmentation. Disabling this might trigger OutOfMemory error in situations that
1386 would otherwise not happen.
1391 When using Mono with the SGen garbage collector this environment
1392 variable can be used to turn on various debugging features of the
1393 collector. The value of this variable is a comma separated list of
1394 words. Do not use these options in production.
1399 Sets the debug level to the specified number.
1401 \fBprint-allowance\fR
1402 After each major collection prints memory consumption for before and
1403 after the collection and the allowance for the minor collector, i.e. how
1404 much the heap is allowed to grow from minor collections before the next
1405 major collection is triggered.
1408 Gathers statistics on the classes whose objects are pinned in the
1409 nursery and for which global remset entries are added. Prints those
1410 statistics when shutting down.
1412 \fBcollect-before-allocs\fR
1414 \fBcheck-remset-consistency\fR
1415 This performs a remset consistency check at various opportunities, and
1416 also clears the nursery at collection time, instead of the default,
1417 when buffers are allocated (clear-at-gc). The consistency check
1418 ensures that there are no major to minor references that are not on
1419 the remembered sets.
1421 \fBmod-union-consistency-check\fR
1422 Checks that the mod-union cardtable is consistent before each
1423 finishing major collection pause. This check is only applicable to
1424 concurrent major collectors.
1426 \fBcheck-mark-bits\fR
1427 Checks that mark bits in the major heap are consistent at the end of
1428 each major collection. Consistent mark bits mean that if an object is
1429 marked, all objects that it had references to must also be marked.
1431 \fBcheck-nursery-pinned\fR
1432 After nursery collections, and before starting concurrent collections,
1433 check whether all nursery objects are pinned, or not pinned -
1434 depending on context. Does nothing when the split nursery collector
1437 \fBxdomain-checks\fR
1438 Performs a check to make sure that no references are left to an
1441 \fBclear-at-tlab-creation\fR
1442 Clears the nursery incrementally when the thread local allocation
1443 buffers (TLAB) are created. The default setting clears the whole
1446 \fBdebug-clear-at-tlab-creation\fR
1447 Clears the nursery incrementally when the thread local allocation
1448 buffers (TLAB) are created, but at GC time fills it with the byte
1449 `0xff`, which should result in a crash more quickly if
1450 `clear-at-tlab-creation` doesn't work properly.
1453 This clears the nursery at GC time instead of doing it when the thread
1454 local allocation buffer (TLAB) is created. The default is to clear
1455 the nursery at TLAB creation time.
1458 Don't do minor collections. If the nursery is full, a major collection
1459 is triggered instead, unless it, too, is disabled.
1462 Don't do major collections.
1464 \fBconservative-stack-mark\fR
1465 Forces the GC to scan the stack conservatively, even if precise
1466 scanning is available.
1468 \fBno-managed-allocator\fR
1469 Disables the managed allocator.
1471 \fBcheck-scan-starts\fR
1472 If set, does a plausibility check on the scan_starts before and after each collection
1474 \fBverify-nursery-at-minor-gc\fR
1475 If set, does a complete object walk of the nursery at the start of each minor collection.
1477 \fBdump-nursery-at-minor-gc\fR
1478 If set, dumps the contents of the nursery at the start of each minor collection. Requires
1479 verify-nursery-at-minor-gc to be set.
1481 \fBheap-dump=\fIfile\fR
1482 Dumps the heap contents to the specified file. To visualize the
1483 information, use the mono-heapviz tool.
1485 \fBbinary-protocol=\fIfile\fR
1486 Outputs the debugging output to the specified file. For this to
1487 work, Mono needs to be compiled with the BINARY_PROTOCOL define on
1488 sgen-gc.c. You can then use this command to explore the output
1490 sgen-grep-binprot 0x1234 0x5678 < file
1493 \fBnursery-canaries\fR
1494 If set, objects allocated in the nursery are suffixed with a canary (guard)
1495 word, which is checked on each minor collection. Can be used to detect/debug
1496 heap corruption issues.
1499 \fBdo-not-finalize(=\fIclasses\fB)\fR
1500 If enabled, finalizers will not be run. Everything else will be
1501 unaffected: finalizable objects will still be put into the
1502 finalization queue where they survive until they're scheduled to
1503 finalize. Once they're not in the queue anymore they will be
1504 collected regularly. If a list of comma-separated class names is
1505 given, only objects from those classes will not be finalized.
1508 \fBlog-finalizers\fR
1509 Log verbosely around the finalization process to aid debugging.
1513 \fBMONO_GAC_PREFIX\fR
1514 Provides a prefix the runtime uses to look for Global Assembly Caches.
1515 Directories are separated by the platform path separator (colons on
1516 unix). MONO_GAC_PREFIX should point to the top directory of a prefixed
1517 install. Or to the directory provided in the gacutil /gacdir command. Example:
1518 .B /home/username/.mono:/usr/local/mono/
1521 Enables some filename rewriting support to assist badly-written
1522 applications that hard-code Windows paths. Set to a colon-separated
1523 list of "drive" to strip drive letters, or "case" to do
1524 case-insensitive file matching in every directory in a path. "all"
1525 enables all rewriting methods. (Backslashes are always mapped to
1526 slashes if this variable is set to a valid option).
1529 For example, this would work from the shell:
1532 MONO_IOMAP=drive:case
1536 If you are using mod_mono to host your web applications, you can use
1539 directive instead, like this:
1542 MonoIOMAP <appalias> all
1545 See mod_mono(8) for more details.
1548 When Mono is using the LLVM code generation backend you can use this
1549 environment variable to pass code generation options to the LLVM
1552 \fBMONO_MANAGED_WATCHER\fR
1553 If set to "disabled", System.IO.FileSystemWatcher will use a file watcher
1554 implementation which silently ignores all the watching requests.
1555 If set to any other value, System.IO.FileSystemWatcher will use the default
1556 managed implementation (slow). If unset, mono will try to use inotify, FAM,
1557 Gamin, kevent under Unix systems and native API calls on Windows, falling
1558 back to the managed implementation on error.
1560 \fBMONO_MESSAGING_PROVIDER\fR
1561 Mono supports a plugin model for its implementation of System.Messaging making
1562 it possible to support a variety of messaging implementations (e.g. AMQP, ActiveMQ).
1563 To specify which messaging implementation is to be used the evironement variable
1564 needs to be set to the full class name for the provider. E.g. to use the RabbitMQ based
1565 AMQP implementation the variable should be set to:
1568 Mono.Messaging.RabbitMQ.RabbitMQMessagingProvider,Mono.Messaging.RabbitMQ
1571 If set causes the mono process to be bound to a single processor. This may be
1572 useful when debugging or working around race conditions.
1575 Disable inlining of thread local accesses. Try setting this if you get a segfault
1576 early on in the execution of mono.
1579 Provides a search path to the runtime where to look for library
1580 files. This is a tool convenient for debugging applications, but
1581 should not be used by deployed applications as it breaks the assembly
1582 loader in subtle ways.
1584 Directories are separated by the platform path separator (colons on unix). Example:
1585 .B /home/username/lib:/usr/local/mono/lib
1587 Relative paths are resolved based on the launch-time current directory.
1589 Alternative solutions to MONO_PATH include: installing libraries into
1590 the Global Assembly Cache (see gacutil(1)) or having the dependent
1591 libraries side-by-side with the main executable.
1593 For a complete description of recommended practices for application
1595 http://www.mono-project.com/docs/getting-started/application-deployment/
1597 \fBMONO_SHARED_DIR\fR
1598 If set its the directory where the ".wapi" handle state is stored.
1599 This is the directory where the Windows I/O Emulation layer stores its
1600 shared state data (files, events, mutexes, pipes). By default Mono
1601 will store the ".wapi" directory in the users's home directory.
1603 \fBMONO_SHARED_HOSTNAME\fR
1604 Uses the string value of this variable as a replacement for the host name when
1605 creating file names in the ".wapi" directory. This helps if the host name of
1606 your machine is likely to be changed when a mono application is running or if
1607 you have a .wapi directory shared among several different computers.
1609 Mono typically uses the hostname to create the files that are used to
1610 share state across multiple Mono processes. This is done to support
1611 home directories that might be shared over the network.
1613 \fBMONO_STRICT_IO_EMULATION\fR
1614 If set, extra checks are made during IO operations. Currently, this
1615 includes only advisory locks around file writes.
1617 \fBMONO_TLS_SESSION_CACHE_TIMEOUT\fR
1618 The time, in seconds, that the SSL/TLS session cache will keep it's entry to
1619 avoid a new negotiation between the client and a server. Negotiation are very
1620 CPU intensive so an application-specific custom value may prove useful for
1621 small embedded systems.
1623 The default is 180 seconds.
1625 \fBMONO_THREADS_PER_CPU\fR
1626 The minimum number of threads in the general threadpool will be
1627 MONO_THREADS_PER_CPU * number of CPUs. The default value for this
1630 \fBMONO_XMLSERIALIZER_THS\fR
1631 Controls the threshold for the XmlSerializer to produce a custom
1632 serializer for a given class instead of using the Reflection-based
1633 interpreter. The possible values are `no' to disable the use of a
1634 custom serializer or a number to indicate when the XmlSerializer
1635 should start serializing. The default value is 50, which means that
1636 the a custom serializer will be produced on the 50th use.
1638 \fBMONO_X509_REVOCATION_MODE\fR
1639 Sets the revocation mode used when validating a X509 certificate chain (https,
1640 ftps, smtps...). The default is 'nocheck', which performs no revocation check
1641 at all. The other possible values are 'offline', which performs CRL check (not
1642 implemented yet) and 'online' which uses OCSP and CRL to verify the revocation
1643 status (not implemented yet).
1646 (Also \fBno_proxy\fR) If both \fBHTTP_PROXY\fR and \fBNO_PROXY\fR are
1647 set, \fBNO_PROXY\fR will be treated as a comma-separated list of "bypass" domains
1648 which will not be sent through the proxy. Domains in \fBNO_PROXY\fR may contain
1649 wildcards, as in "*.mono-project.com" or "build????.local". Not supported on
1650 Windows, Mac OS, iOS or Android.
1651 .SH ENVIRONMENT VARIABLES FOR DEBUGGING
1653 \fBMONO_ASPNET_NODELETE\fR
1654 If set to any value, temporary source files generated by ASP.NET support
1655 classes will not be removed. They will be kept in the user's temporary
1659 If set, enables some features of the runtime useful for debugging.
1660 This variable should contain a comma separated list of debugging options.
1661 Currently, the following options are supported:
1665 \fBalign-small-structs\fR
1666 Enables small structs alignment to 4/8 bytes.
1668 \fBarm-use-fallback-tls\fR
1669 When this option is set on ARM, a fallback thread local store will be used instead
1670 of the default fast thread local storage primitives.
1672 \fBbreak-on-unverified\fR
1673 If this variable is set, when the Mono VM runs into a verification
1674 problem, instead of throwing an exception it will break into the
1675 debugger. This is useful when debugging verifier problems
1678 This option can be used to get more detailed information from
1679 InvalidCast exceptions, it will provide information about the types
1682 \fBcheck-pinvoke-callconv\fR
1683 This option causes the runtime to check for calling convention
1684 mismatches when using pinvoke, i.e. mixing cdecl/stdcall. It only
1685 works on windows. If a mismatch is detected, an
1686 ExecutionEngineException is thrown.
1688 \fBcollect-pagefault-stats\fR
1689 Collects information about pagefaults. This is used internally to
1690 track the number of page faults produced to load metadata. To display
1691 this information you must use this option with "--stats" command line
1694 \fBdebug-domain-unload\fR
1695 When this option is set, the runtime will invalidate the domain memory
1696 pool instead of destroying it.
1698 \fBdisable_omit_fp\fR
1699 Disables a compiler optimization where the frame pointer is omitted
1700 from the stack. This optimization can interact badly with debuggers.
1702 \fBdont-free-domains\fR
1703 This is an Optimization for multi-AppDomain applications (most
1704 commonly ASP.NET applications). Due to internal limitations Mono,
1705 Mono by default does not use typed allocations on multi-appDomain
1706 applications as they could leak memory when a domain is unloaded.
1708 Although this is a fine default, for applications that use more than
1709 on AppDomain heavily (for example, ASP.NET applications) it is worth
1710 trading off the small leaks for the increased performance
1711 (additionally, since ASP.NET applications are not likely going to
1712 unload the application domains on production systems, it is worth
1713 using this feature).
1715 \fBdyn-runtime-invoke\fR
1716 Instructs the runtime to try to use a generic runtime-invoke wrapper
1717 instead of creating one invoke wrapper.
1719 \fBexplicit-null-checks\fR
1720 Makes the JIT generate an explicit NULL check on variable dereferences
1721 instead of depending on the operating system to raise a SIGSEGV or
1722 another form of trap event when an invalid memory location is
1726 Equivalent to setting the \fBMONO_XDEBUG\fR variable, this emits
1727 symbols into a shared library as the code is JITed that can be loaded
1728 into GDB to inspect symbols.
1730 \fBgen-seq-points\fR
1731 Automatically generates sequence points where the
1732 IL stack is empty. These are places where the debugger can set a
1735 \fBno-compact-seq-points\fR
1736 Unless the option is used, the runtime generates sequence points data that
1737 maps native offsets to IL offsets. Sequence point data is used to
1738 display IL offset in stacktraces. Stacktraces with IL offsets can be
1739 symbolicated using mono-symbolicate tool.
1742 Captures the interrupt signal (Control-C) and displays a stack trace
1743 when pressed. Useful to find out where the program is executing at a
1744 given point. This only displays the stack trace of a single thread.
1747 Instructs the runtime to initialize the stack with
1748 some known values (0x2a on x86-64) at the start of a method to assist
1749 in debuggin the JIT engine.
1751 \fBkeep-delegates\fR
1752 This option will leak delegate trampolines that are no longer
1753 referenced as to present the user with more information about a
1754 delegate misuse. Basically a delegate instance might be created,
1755 passed to unmanaged code, and no references kept in managed code,
1756 which will garbage collect the code. With this option it is possible
1757 to track down the source of the problems.
1759 \fBno-gdb-backtrace\fR
1760 This option will disable the GDB backtrace emitted by the runtime
1761 after a SIGSEGV or SIGABRT in unmanaged code.
1763 \fBpartial-sharing\fR
1764 When this option is set, the runtime can share generated code between
1765 generic types effectively reducing the amount of code generated.
1767 \fBreverse-pinvoke-exceptions
1768 This option will cause mono to abort with a descriptive message when
1769 during stack unwinding after an exception it reaches a native stack
1770 frame. This happens when a managed delegate is passed to native code,
1771 and the managed delegate throws an exception. Mono will normally try
1772 to unwind the stack to the first (managed) exception handler, and it
1773 will skip any native stack frames in the process. This leads to
1774 undefined behaviour (since mono doesn't know how to process native
1775 frames), leaks, and possibly crashes too.
1777 \fBsingle-imm-size\fR
1778 This guarantees that each time managed code is compiled the same
1779 instructions and registers are used, regardless of the size of used
1782 \fBsoft-breakpoints\fR
1783 This option allows using single-steps and breakpoints in hardware
1784 where we cannot do it with signals.
1786 \fBsuspend-on-native-crash\fR
1787 This option will suspend the program when a native crash occurs (SIGSEGV, SIGILL, ...).
1788 This is useful for debugging crashes which do not happen under gdb,
1789 since a live process contains more information than a core file.
1791 \fBsuspend-on-sigsegv\fR
1792 Same as \fBsuspend-on-native-crash\fR.
1794 \fBsuspend-on-exception\fR
1795 This option will suspend the program when an exception occurs.
1797 \fBsuspend-on-unhandled\fR
1798 This option will suspend the program when an unhandled exception occurs.
1800 \fBthread-dump-dir=DIR\fR
1801 Use DIR for storage thread dumps created by SIGQUIT.
1804 Make gdb output on native crashes more verbose.
1808 \fBMONO_LOG_LEVEL\fR
1809 The logging level, possible values are `error', `critical', `warning',
1810 `message', `info' and `debug'. See the DEBUGGING section for more
1814 Controls the domain of the Mono runtime that logging will apply to.
1815 If set, the log mask is changed to the set value. Possible values are
1816 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1817 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1818 "security" (e.g. Moonlight CoreCLR support) and "all".
1819 The default value is "all". Changing the mask value allows you to display only
1820 messages for a certain component. You can use multiple masks by comma
1821 separating them. For example to see config file messages and assembly loader
1822 messages set you mask to "asm,cfg".
1825 Controls where trace log messages are written. If not set then the messages go to stdout.
1826 If set, the string either specifies a path to a file that will have messages appended to
1827 it, or the string "syslog" in which case the messages will be written to the system log.
1828 Under Windows, this is simulated by writing to a file called "mono.log".
1829 \fBMONO_LOG_HEADER\fR
1830 Controls whether trace log messages not directed to syslog have the id, timestamp, and
1831 pid as the prefix to the log message. To enable a header this environment variable need
1835 Used for runtime tracing of method calls. The format of the comma separated
1844 disabled Trace output off upon start.
1847 You can toggle trace output on/off sending a SIGUSR2 signal to the program.
1849 \fBMONO_TRACE_LISTENER\fR
1850 If set, enables the System.Diagnostics.DefaultTraceListener, which will
1851 print the output of the System.Diagnostics Trace and Debug classes.
1852 It can be set to a filename, and to Console.Out or Console.Error to display
1853 output to standard output or standard error, respectively. If it's set to
1854 Console.Out or Console.Error you can append an optional prefix that will
1855 be used when writing messages like this: Console.Error:MyProgramName.
1856 See the System.Diagnostics.DefaultTraceListener documentation for more
1859 \fBMONO_WCF_TRACE\fR
1860 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.
1862 \fBMONO_XEXCEPTIONS\fR
1863 This throws an exception when a X11 error is encountered; by default a
1864 message is displayed but execution continues
1866 \fBMONO_XMLSERIALIZER_DEBUG\fR
1867 Set this value to 1 to prevent the serializer from removing the
1868 temporary files that are created for fast serialization; This might
1869 be useful when debugging.
1872 This is used in the System.Windows.Forms implementation when running
1873 with the X11 backend. This is used to debug problems in Windows.Forms
1874 as it forces all of the commands send to X11 server to be done
1875 synchronously. The default mode of operation is asynchronous which
1876 makes it hard to isolate the root of certain problems.
1879 When the the MONO_XDEBUG env var is set, debugging info for JITted
1880 code is emitted into a shared library, loadable into gdb. This enables,
1881 for example, to see managed frame names on gdb backtraces.
1883 \fBMONO_VERBOSE_METHOD\fR
1884 Enables the maximum JIT verbosity for the specified method. This is
1885 very helpfull to diagnose a miscompilation problems of a specific
1886 method. This can be a comma-separated list of method names to
1887 match. If the name is simple, this applies to any method with that
1888 name, otherwise you can use a mono method description (see the section
1889 METHOD DESCRIPTIONS).
1891 \fBMONO_JIT_DUMP_METHOD\fR
1892 Enables sending of the JITs intermediate representation for a specified
1893 method to the IdealGraphVisualizer tool.
1895 \fBMONO_VERBOSE_HWCAP\fR
1896 If set, makes the JIT output information about detected CPU features
1897 (such as SSE, CMOV, FCMOV, etc) to stdout.
1899 \fBMONO_CONSERVATIVE_HWCAP\fR
1900 If set, the JIT will not perform any hardware capability detection. This
1901 may be useful to pinpoint the cause of JIT issues. This is the default
1902 when Mono is built as an AOT cross compiler, so that the generated code
1903 will run on most hardware.
1905 If you want to use Valgrind, you will find the file `mono.supp'
1906 useful, it contains the suppressions for the GC which trigger
1907 incorrect warnings. Use it like this:
1909 valgrind --suppressions=mono.supp mono ...
1912 On some platforms, Mono can expose a set of DTrace probes (also known
1913 as user-land statically defined, USDT Probes).
1915 They are defined in the file `mono.d'.
1917 .B ves-init-begin, ves-init-end
1919 Begin and end of runtime initialization.
1921 .B method-compile-begin, method-compile-end
1923 Begin and end of method compilation.
1924 The probe arguments are class name, method name and signature,
1925 and in case of method-compile-end success or failure of compilation.
1929 Begin and end of Garbage Collection.
1931 To verify the availability of the probes, run:
1933 dtrace -P mono'$target' -l -c mono
1936 Mono's Ping implementation for detecting network reachability can
1937 create the ICMP packets itself without requiring the system ping
1938 command to do the work. If you want to enable this on Linux for
1939 non-root users, you need to give the Mono binary special permissions.
1941 As root, run this command:
1943 # setcap cap_net_raw=+ep /usr/bin/mono
1946 On Unix assemblies are loaded from the installation lib directory. If you set
1947 `prefix' to /usr, the assemblies will be located in /usr/lib. On
1948 Windows, the assemblies are loaded from the directory where mono and
1951 .B ~/.mono/aot-cache
1953 The directory for the ahead-of-time compiler demand creation
1954 assemblies are located.
1956 .B /etc/mono/config, ~/.mono/config
1958 Mono runtime configuration file. See the mono-config(5) manual page
1959 for more information.
1961 .B ~/.config/.mono/certs, /usr/share/.mono/certs
1963 Contains Mono certificate stores for users / machine. See the certmgr(1)
1964 manual page for more information on managing certificate stores and
1965 the mozroots(1) page for information on how to import the Mozilla root
1966 certificates into the Mono certificate store.
1968 .B ~/.mono/assemblies/ASSEMBLY/ASSEMBLY.config
1970 Files in this directory allow a user to customize the configuration
1971 for a given system assembly, the format is the one described in the
1972 mono-config(5) page.
1974 .B ~/.config/.mono/keypairs, /usr/share/.mono/keypairs
1976 Contains Mono cryptographic keypairs for users / machine. They can be
1977 accessed by using a CspParameters object with DSACryptoServiceProvider
1978 and RSACryptoServiceProvider classes.
1980 .B ~/.config/.isolatedstorage, ~/.local/share/.isolatedstorage, /usr/share/.isolatedstorage
1982 Contains Mono isolated storage for non-roaming users, roaming users and
1983 local machine. Isolated storage can be accessed using the classes from
1984 the System.IO.IsolatedStorage namespace.
1986 .B <assembly>.config
1988 Configuration information for individual assemblies is loaded by the
1989 runtime from side-by-side files with the .config files, see the
1990 http://www.mono-project.com/Config for more information.
1992 .B Web.config, web.config
1994 ASP.NET applications are configured through these files, the
1995 configuration is done on a per-directory basis. For more information
1996 on this subject see the http://www.mono-project.com/Config_system.web
1999 Mailing lists are listed at the
2000 http://www.mono-project.com/community/help/mailing-lists/
2002 http://www.mono-project.com
2005 \fBcertmgr\fR(1), \fBcert-sync\fR(1), \fBcsharp\fR(1),
2006 \fBgacutil\fR(1), \fBmcs\fR(1), \fBmonodis\fR(1),
2007 \fBmono-config\fR(5), \fBmono\-profilers\fR(1),
2008 \fBmprof\-report\fR(1), \fBpdb2mdb\fR(1), \fBxsp\fR(1),
2011 For more information on AOT:
2012 http://www.mono-project.com/docs/advanced/aot/
2014 For ASP.NET-related documentation, see the xsp(1) manual page