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.
69 The following options are available:
71 \fB--aot\fR, \fB--aot[=options]\fR
72 This option is used to precompile the CIL code in the specified
73 assembly to native code. The generated code is stored in a file with
74 the extension .so. This file will be automatically picked up by the
75 runtime when the assembly is executed.
77 Ahead-of-Time compilation is most useful if you use it in combination
78 with the -O=all,-shared flag which enables all of the optimizations in
79 the code generator to be performed. Some of those optimizations are
80 not practical for Just-in-Time compilation since they might be very
83 Unlike the .NET Framework, Ahead-of-Time compilation will not generate
84 domain independent code: it generates the same code that the
85 Just-in-Time compiler would produce. Since most applications use a
86 single domain, this is fine. If you want to optimize the generated
87 code for use in multi-domain applications, consider using the
90 This pre-compiles the methods, but the original assembly is still
91 required to execute as this one contains the metadata and exception
92 information which is not available on the generated file. When
93 precompiling code, you might want to compile with all optimizations
94 (-O=all). Pre-compiled code is position independent code.
96 Precompilation is just a mechanism to reduce startup time, increase
97 code sharing across multiple mono processes and avoid just-in-time
98 compilation program startup costs. The original assembly must still
99 be present, as the metadata is contained there.
101 AOT code typically can not be moved from one computer to another
102 (CPU-specific optimizations that are detected at runtime) so you
103 should not try to move the pre-generated assemblies or package the
104 pre-generated assemblies for deployment.
106 A few options are available as a parameter to the
108 command line option. The options are separated by commas, and more
109 than one can be specified:
114 Instructs the AOT compiler to output assembly code instead of an
117 .I bind-to-runtime-version
119 If specified, forces the generated AOT files to be bound to the
120 runtime version of the compiling Mono. This will prevent the AOT
121 files from being consumed by a different Mono runtime.
123 .I data-outfile=FILE.dll.aotdata
125 This instructs the AOT code generator to output certain data
126 constructs into a separate file. This can reduce the executable
127 images some five to twenty percent. Developers need to then ship the
128 resulting aotdata as a resource and register a hook to load the data
129 on demand by using the
130 .I mono_install_load_aot_data_hook
135 When this option is specified, icalls (internal calls made from the
136 standard library into the mono runtime code) are invoked directly
137 instead of going through the operating system symbol lookup operation.
138 This requires use of the
144 When this option is specified, P/Invoke methods are invoked directly
145 instead of going through the operating system symbol lookup operation.
146 This requires use of the
151 Instructs the AOT compiler to emit DWARF debugging information. When
152 used together with the nodebug option, only DWARF debugging
153 information is emitted, but not the information that can be used at
158 This creates binaries which can be used with the --full-aot option.
162 This creates binaries which can be used with the --hybrid-aot option.
165 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.
168 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
172 automatically enables the
176 options. This feature is experimental.
178 .I llvm-outfile=[filename]
179 Gives the path for the temporary LLVM bitcode file created during AOT.
181 Each AOT module will typically contain the code for inflated methods and wrappers that
182 are called by code in that module. In dedup mode, we identify and skip compiling all of those
183 methods. When using this mode with fullaot, dedup-include is required or these methods will
186 .I dedup-include=[filename]
187 In dedup-include mode, we are in the pass of compilation where we compile the methods
188 that we had previously skipped. All of them are emitted into the assembly that is passed
189 as this option. We consolidate the many duplicate skipped copies of the same method into one.
193 Print the architecture the AOT in this copy of Mono targets and quit.
196 Generates all required wrappers, so that it is possible to run --interpreter without
197 any code generation at runtime. This option only makes sense with \fBmscorlib.dll\fR.
201 mono_jit_set_aot_mode (MONO_AOT_MODE_INTERP);
206 Additional flags to pass to the C linker (if the current AOT mode calls for invoking it).
208 .I llvm-path=<PREFIX>
209 Same for the llvm tools 'opt' and 'llc'.
212 Instructs the AOT compiler to generate offline sequence points .msym files.
213 The generated .msym files will be stored into a subfolder of <PATH> named as the
217 Use the GNU style target triple <TRIPLE> to determine some code generation options, i.e.
218 --mtriple=armv7-linux-gnueabi will generate code that targets ARMv7. This is currently
219 only supported by the ARM backend. In LLVM mode, this triple is passed on to the LLVM
222 .I nimt-trampolines=[number]
223 When compiling in full aot mode, the IMT trampolines must be precreated
224 in the AOT image. You can add additional method trampolines with this argument.
227 .I ngsharedvt-trampolines=[number]
228 When compiling in full aot mode, the value type generic sharing trampolines must be precreated
229 in the AOT image. You can add additional method trampolines with this argument.
233 Instructs the AOT compiler to not output any debugging information.
236 This prevents the AOT compiler from generating a direct calls to a
237 method. The AOT compiler usually generates direct calls for certain
238 methods that do not require going through the PLT (for example,
239 methods that are known to not require a hook like a static
240 constructor) or call into simple internal calls.
242 .I nrgctx-trampolines=[number]
243 When compiling in full aot mode, the generic sharing trampolines must be precreated
244 in the AOT image. You can add additional method trampolines with this argument.
247 .I nrgctx-fetch-trampolines=[number]
248 When compiling in full aot mode, the generic sharing fetch trampolines must be precreated
249 in the AOT image. You can add additional method trampolines with this argument.
252 .I ntrampolines=[number]
253 When compiling in full aot mode, the method trampolines must be precreated
254 in the AOT image. You can add additional method trampolines with this argument.
257 .I outfile=[filename]
258 Instructs the AOT compiler to save the output to the specified file.
260 .I print-skipped-methods
261 If the AOT compiler cannot compile a method for any reason, enabling this flag
262 will output the skipped methods to the console.
265 Specify a file to use for profile-guided optimization. See the \fBAOT profiler\fR sub-section. To specify multiple files, include the
267 option multiple times.
270 AOT *only* the methods described in the files specified with the
272 option. See the \fBAOT profiler\fR sub-section.
274 .I readonly-value=namespace.typename.fieldname=type/value
275 Override the value of a static readonly field. Usually, during JIT
276 compilation, the static constructor is ran eagerly, so the value of
277 a static readonly field is known at compilation time and the compiler
278 can do a number of optimizations based on it. During AOT, instead, the static
279 constructor can't be ran, so this option can be used to set the value of such
280 a field and enable the same set of optimizations.
281 Type can be any of i1, i2, i4 for integers of the respective sizes (in bytes).
282 Note that signed/unsigned numbers do not matter here, just the storage size.
283 This option can be specified multiple times and it doesn't prevent the static
284 constructor for the type defining the field to execute with the usual rules
285 at runtime (hence possibly computing a different value for the field).
287 .I save-temps,keep-temps
288 Instructs the AOT compiler to keep temporary files.
291 This instructs the compiler to generate sequence point checks that
292 allow Mono's soft debugger to debug applications even on systems where
293 it is not possible to set breakpoints or to single step (certain
294 hardware configurations like the cell phones and video gaming
298 Create an ELF object file (.o) or .s file which can be statically linked into an
299 executable when embedding the mono runtime. When this option is used, the object file
300 needs to be registered with the embedded runtime using the mono_aot_register_module
301 function which takes as its argument the mono_aot_module_<ASSEMBLY NAME>_info global
302 symbol from the object file:
305 extern void *mono_aot_module_hello_info;
307 mono_aot_register_module (mono_aot_module_hello_info);
312 Print various stats collected during AOT compilation.
315 Explicitly specify path to store temporary files created during AOT compilation.
318 This is an experimental option for the AOT compiler to use multiple threads
319 when compiling the methods.
321 .I tool-prefix=<PREFIX>
322 Prepends <PREFIX> to the name of tools ran by the AOT compiler, i.e. 'as'/'ld'. For
323 example, --tool=prefix=arm-linux-gnueabi- will make the AOT compiler run
324 'arm-linux-gnueabi-as' instead of 'as'.
327 Prints additional information about type loading failures.
329 .I write-symbols,no-write-symbols
330 Instructs the AOT compiler to emit (or not emit) debug symbol information.
332 For more information about AOT, see: http://www.mono-project.com/docs/advanced/aot/
335 \fB--aot-path=PATH\fR
336 List of additional directories to search for AOT images.
338 \fB--apply-bindings=FILE\fR
339 Apply the assembly bindings from the specified configuration file when running
340 the AOT compiler. This is useful when compiling an auxiliary assembly that is
341 referenced by a main assembly that provides a configuration file. For example,
342 if app.exe uses lib.dll then in order to make the assembly bindings from
343 app.exe.config available when compiling lib.dll ahead of time, use:
345 mono --apply-bindings=app.exe.config --aot lib.dll
348 \fB--assembly-loader=MODE\fR
349 If mode is \fBstrict\fR, Mono will check that the public key token, culture and version
350 of a candidate assembly matches the requested strong name. If mode is \fBlegacy\fR, as
351 long as the name matches, the candidate will be allowed. \fBstrict\fR is the behavior
352 consistent with .NET Framework but may break some existing mono-based applications.
353 The default is \fBlegacy\fR.
355 \fB--attach=[options]\fR
356 Currently the only option supported by this command line argument is
357 \fBdisable\fR which disables the attach functionality.
359 \fB--config filename\fR
360 Load the specified configuration file instead of the default one(s).
361 The default files are /etc/mono/config and ~/.mono/config or the file
362 specified in the MONO_CONFIG environment variable, if set. See the
363 mono-config(5) man page for details on the format of this file.
365 \fB--debugger-agent=[options]\fR
366 This instructs the Mono runtime to
367 start a debugging agent inside the Mono runtime and connect it to a
368 client user interface will control the Mono process.
369 This option is typically used by IDEs, like the MonoDevelop or Visual Studio IDEs.
371 The configuration is specified using one of more of the following options:
377 Use this option to specify the IP address where your debugger client is
382 Specifies the diagnostics log level for
386 Used to specify the file where the log will be stored, it defaults to
390 Defaults to no, with the default option Mono will actively connect to the
391 host/port configured with the \fBaddress\fR option. If you set it to 'y', it
392 instructs the Mono runtime to start debugging in server mode, where Mono
393 actively waits for the debugger front end to connect to the Mono process.
394 Mono will print out to stdout the IP address and port where it is listening.
397 If set to yes, Mono will call \fBsetpgid(0, 0)\fR on startup, if that function
398 is available on the system. This is useful for ensuring that signals delivered
399 to a process that is executing the debuggee are not propagated to the debuggee,
400 e.g. when Ctrl-C sends \fBSIGINT\fR to the \fBsdb\fR tool.
403 Defaults to yes, with the default option Mono will suspend the vm on startup
404 until it connects successfully to a debugger front end. If you set it to 'n', in
405 conjunction with \fBserver=y\fR, it instructs the Mono runtime to run as normal,
406 while caching metadata to send to the debugger front end on connection..
408 .I transport=transport_name
410 This is used to specify the transport that the debugger will use to
411 communicate. It must be specified and currently requires this to
417 Configures the virtual machine to be better suited for desktop
418 applications. Currently this sets the GC system to avoid expanding
419 the heap as much as possible at the expense of slowing down garbage
423 This flag instructs the Mono runtime to not
424 generate any code at runtime and depend exclusively on the code
425 generated from using mono --aot=full previously. This is useful for
426 platforms that do not permit dynamic code generation, or if you need
427 to run assemblies that have been stripped of IL (for example using
430 Notice that this feature will abort execution at runtime if a codepath
431 in your program, or Mono's class libraries attempts to generate code
432 dynamically. You should test your software upfront and make sure that
433 you do not use any dynamic features.
435 \fB--gc=boehm\fR, \fB--gc=sgen\fR
436 Selects the Garbage Collector engine for Mono to use, Boehm or SGen.
437 Currently this merely ensures that you are running either the
438 \fImono\fR or \fImono-sgen\fR commands. This flag can be set in the
439 \fBMONO_ENV_OPTIONS\fR environment variable to force all of your child
440 processes to use one particular kind of GC with the Mono runtime.
442 \fB--gc-debug=[options]\fR
443 Command line equivalent of the \fBMONO_GC_DEBUG\fR environment variable.
445 \fB--gc-params=[options]\fR
446 Command line equivalent of the \fBMONO_GC_PARAMS\fR environment variable.
448 \fB--arch=32\fR, \fB--arch=64\fR
449 (Mac OS X only): Selects the bitness of the Mono binary used, if
450 available. If the binary used is already for the selected bitness, nothing
451 changes. If not, the execution switches to a binary with the selected
452 bitness suffix installed side by side (for example, '/bin/mono --arch=64'
453 will switch to '/bin/mono64' iff '/bin/mono' is a 32-bit build).
455 \fB--help\fR, \fB-h\fR
456 Displays usage instructions.
459 The Mono runtime will use its interpreter to execute a given assembly.
460 The interpreter is usually slower than the JIT, but it can be useful on
461 platforms where code generation at runtime is not allowed.
464 This flag allows the Mono runtime to run assemblies
465 that have been stripped of IL, for example using mono-cil-strip. For this to
466 work, the assembly must have been AOT compiled with --aot=hybrid.
468 This flag is similar to --full-aot, but it does not disable the JIT. This means
469 you can use dynamic features such as System.Reflection.Emit.
472 If the Mono runtime has been compiled with LLVM support (not available
473 in all configurations), Mono will use the LLVM optimization and code
474 generation engine to JIT or AOT compile.
476 For more information, consult: http://www.mono-project.com/docs/advanced/mono-llvm/
479 When using a Mono that has been compiled with LLVM support, it forces
480 Mono to fallback to its JIT engine and not use the LLVM backend.
482 \fB--optimize=MODE\fR, \fB-O=MODE\fR
483 MODE is a comma separated list of optimizations. They also allow
484 optimizations to be turned off by prefixing the optimization name with
487 In general, Mono has been tuned to use the default set of flags,
488 before using these flags for a deployment setting, you might want to
489 actually measure the benefits of using them.
491 The following optimization flags are implemented in the core engine:
493 abcrem Array bound checks removal
494 all Turn on all optimizations
495 aot Usage of Ahead Of Time compiled code
496 branch Branch optimizations
497 cfold Constant folding
498 cmov Conditional moves [arch-dependency]
499 deadce Dead code elimination
500 consprop Constant propagation
501 copyprop Copy propagation
502 fcmov Fast x86 FP compares [arch-dependency]
503 float32 Perform 32-bit float arithmetic using 32-bit operations
504 gshared Enable generic code sharing.
505 inline Inline method calls
506 intrins Intrinsic method implementations
507 linears Linear scan global reg allocation
508 leaf Leaf procedures optimizations
509 loop Loop related optimizations
510 peephole Peephole postpass
511 precomp Precompile all methods before executing Main
512 sched Instruction scheduling
513 shared Emit per-domain code
514 sse2 SSE2 instructions on x86 [arch-dependency]
515 tailc Tail recursion and tail calls
518 For example, to enable all the optimization but dead code
519 elimination and inlining, you can use:
521 -O=all,-deadce,-inline
524 The flags that are flagged with [arch-dependency] indicate that the
525 given option if used in combination with Ahead of Time compilation
526 (--aot flag) would produce pre-compiled code that will depend on the
527 current CPU and might not be safely moved to another computer.
531 The following optimizations are supported
534 Requests that the runtime performn 32-bit floating point operations
535 using only 32-bits. By default the Mono runtime tries to use the
536 highest precision available for floating point operations, but while
537 this might render better results, the code might run slower. This
538 options also affects the code generated by the LLVM backend.
541 Controls whether the runtime should attempt to inline (the default),
542 or not inline methods invocations
546 \fB--runtime=VERSION\fR
547 Mono supports different runtime versions. The version used depends on the program
548 that is being run or on its configuration file (named program.exe.config). This option
549 can be used to override such autodetection, by forcing a different runtime version
550 to be used. Note that this should only be used to select a later compatible runtime
551 version than the one the program was compiled against. A typical usage is for
552 running a 1.1 program on a 2.0 version:
554 mono --runtime=v2.0.50727 program.exe
557 \fB--security\fR, \fB--security=mode\fR
558 Activate the security manager, a currently experimental feature in
559 Mono and it is OFF by default. The new code verifier can be enabled
560 with this option as well.
564 Using security without parameters is equivalent as calling it with the
567 The following modes are supported:
570 Enables the core-clr security system, typically used for
571 Moonlight/Silverlight applications. It provides a much simpler
572 security system than CAS, see http://www.mono-project.com/docs/web/moonlight/
573 for more details and links to the descriptions of this new system.
576 Enables the new verifier and performs basic verification for code
577 validity. In this mode, unsafe code and P/Invoke are allowed. This
578 mode provides a better safety guarantee but it is still possible
579 for managed code to crash Mono.
582 Enables the new verifier and performs full verification of the code
583 being executed. It only allows verifiable code to be executed.
584 Unsafe code is not allowed but P/Invoke is. This mode should
585 not allow managed code to crash mono. The verification is not as
586 strict as ECMA 335 standard in order to stay compatible with the MS
589 The security system acts on user code: code contained in mscorlib or
590 the global assembly cache is always trusted.
595 Configures the virtual machine to be better suited for server
596 operations (currently, allows a heavier threadpool initialization).
599 Verifies mscorlib and assemblies in the global
600 assembly cache for valid IL, and all user code for IL
603 This is different from \fB--security\fR's verifiable
604 or validil in that these options only check user code and skip
605 mscorlib and assemblies located on the global assembly cache.
607 \fB-V\fR, \fB--version\fR
608 Prints JIT version information (system configuration, release number
609 and branch names if available).
612 .SH DEVELOPMENT OPTIONS
613 The following options are used to help when developing a JITed application.
615 \fB--debug\fR, \fB--debug=OPTIONS\fR
616 Turns on the debugging mode in the runtime. If an assembly was
617 compiled with debugging information, it will produce line number
618 information for stack traces.
622 The optional OPTIONS argument is a comma separated list of debugging
623 options. These options are turned off by default since they generate
624 much larger and slower code at runtime.
626 The following options are supported:
629 Produces a detailed error when throwing a InvalidCastException. This
630 option needs to be enabled as this generates more verbose code at
634 Disable some JIT optimizations which are usually only disabled when
635 running inside the debugger. This can be helpful if you want to attach
636 to the running process with mdb.
639 Generate and register debugging information with gdb. This is only supported on some
640 platforms, and only when using gdb 7.0 or later.
644 \fB\-\-profile\fR[=\fIprofiler\fR[:\fIprofiler_args\fR]]\fR
645 Loads a profiler module with the given arguments. For more information,
646 see the \fBPROFILING\fR section.
648 This option can be used multiple times; each time will load an additional
651 \fB--trace[=expression]\fR
652 Shows method names as they are invoked. By default all methods are
655 The trace can be customized to include or exclude methods, classes or
656 assemblies. A trace expression is a comma separated list of targets,
657 each target can be prefixed with a minus sign to turn off a particular
658 target. The words `program', `all' and `disabled' have special
659 meaning. `program' refers to the main program being executed, and
660 `all' means all the method calls.
662 The `disabled' option is used to start up with tracing disabled. It
663 can be enabled at a later point in time in the program by sending the
664 SIGUSR2 signal to the runtime.
666 Assemblies are specified by their name, for example, to trace all
667 calls in the System assembly, use:
670 mono --trace=System app.exe
673 Classes are specified with the T: prefix. For example, to trace all
674 calls to the System.String class, use:
677 mono --trace=T:System.String app.exe
680 And individual methods are referenced with the M: prefix, and the
681 standard method notation:
684 mono --trace=M:System.Console:WriteLine app.exe
687 Exceptions can also be traced, it will cause a stack trace to be
688 printed every time an exception of the specified type is thrown.
689 The exception type can be specified with or without the namespace,
690 and to trace all exceptions, specify 'all' as the type name.
693 mono --trace=E:System.Exception app.exe
696 As previously noted, various rules can be specified at once:
699 mono --trace=T:System.String,T:System.Random app.exe
702 You can exclude pieces, the next example traces calls to
703 System.String except for the System.String:Concat method.
706 mono --trace=T:System.String,-M:System.String:Concat
709 You can trace managed to unmanaged transitions using
710 the wrapper qualifier:
713 mono --trace=wrapper app.exe
716 Finally, namespaces can be specified using the N: prefix:
719 mono --trace=N:System.Xml
723 \fB--no-x86-stack-align\fR
724 Don't align stack frames on the x86 architecture. By default, Mono
725 aligns stack frames to 16 bytes on x86, so that local floating point
726 and SIMD variables can be properly aligned. This option turns off the
727 alignment, which usually saves one instruction per call, but might
728 result in significantly lower floating point and SIMD performance.
731 Generate a JIT method map in a /tmp/perf-PID.map file. This file is then
732 used, for example, by the perf tool included in recent Linux kernels.
733 Each line in the file has:
736 HEXADDR HEXSIZE methodname
739 Currently this option is only supported on Linux.
740 .SH JIT MAINTAINER OPTIONS
741 The maintainer options are only used by those developing the runtime
742 itself, and not typically of interest to runtime users or developers.
744 \fB--bisect=optimization:filename\fR
745 This flag is used by the automatic optimization bug bisector. It
746 takes an optimization flag and a filename of a file containing a list
747 of full method names, one per line. When it compiles one of the
748 methods in the file it will use the optimization given, in addition to
749 the optimizations that are otherwise enabled. Note that if the
750 optimization is enabled by default, you should disable it with `-O`,
751 otherwise it will just apply to every method, whether it's in the file
755 Inserts a breakpoint before the method whose name is `method'
756 (namespace.class:methodname). Use `Main' as method name to insert a
757 breakpoint on the application's main method. You can use it also with
758 generics, for example "System.Collections.Generic.Queue`1:Peek"
761 Inserts a breakpoint on exceptions. This allows you to debug your
762 application with a native debugger when an exception is thrown.
765 This compiles a method (namespace.name:methodname), this is used for
766 testing the compiler performance or to examine the output of the code
770 Compiles all the methods in an assembly. This is used to test the
771 compiler performance or to examine the output of the code generator
773 \fB--graph=TYPE METHOD\fR
774 This generates a postscript file with a graph with the details about
775 the specified method (namespace.name:methodname). This requires `dot'
776 and ghostview to be installed (it expects Ghostview to be called
779 The following graphs are available:
781 cfg Control Flow Graph (CFG)
783 code CFG showing code
784 ssa CFG showing code after SSA translation
785 optcode CFG showing code after IR optimizations
788 Some graphs will only be available if certain optimizations are turned
792 Instruct the runtime on the number of times that the method specified
793 by --compile (or all the methods if --compileall is used) to be
794 compiled. This is used for testing the code generator performance.
797 Displays information about the work done by the runtime during the
798 execution of an application.
800 \fB--wapi=hps|semdel\fR
801 Perform maintenance of the process shared data.
803 semdel will delete the global semaphore.
805 hps will list the currently used handles.
807 \fB-v\fR, \fB--verbose\fR
808 Increases the verbosity level, each time it is listed, increases the
809 verbosity level to include more information (including, for example,
810 a disassembly of the native code produced, code selector info etc.).
812 The Mono runtime allows external processes to attach to a running
813 process and load assemblies into the running program. To attach to
814 the process, a special protocol is implemented in the Mono.Management
817 With this support it is possible to load assemblies that have an entry
818 point (they are created with -target:exe or -target:winexe) to be
819 loaded and executed in the Mono process.
821 The code is loaded into the root domain, and it starts execution on
822 the special runtime attach thread. The attached program should
823 create its own threads and return after invocation.
825 This support allows for example debugging applications by having the
826 csharp shell attach to running processes.
828 The Mono runtime includes a profiler API that dynamically loaded
829 profiler modules and embedders can use to collect performance-related
830 data about an application. Profiler modules are loaded by passing the
831 \fB\-\-profile\fR command line argument to the Mono runtime.
833 Mono ships with a few profiler modules, of which the \fBlog\fR profiler
834 is the most feature-rich. It is also the default profiler if the
835 \fIprofiler\fR argument is not given, or if \fBdefault\fR is given.
836 It is possible to write your own profiler modules; see the
837 \fBCustom profilers\fR sub-section.
839 The log profiler can be used to collect a lot of information about
840 a program running in the Mono runtime. This data can be used (both
841 while the process is running and later) to do analyses of the
842 program behavior, determine resource usage, performance issues or
843 even look for particular execution patterns.
845 This is accomplished by logging the events provided by the Mono
846 runtime through the profiler API and periodically writing them to a
847 file which can later be inspected with the \fBmprof\-report\fR(1)
850 More information about how to use the log profiler is available on
851 the \fBmono\-profilers\fR(1) page, under the \fBLOG PROFILER\fR
852 section, as well as the \fBmprof\-report\fR(1) page.
853 .SS Coverage profiler
854 The code coverage profiler can instrument a program to help determine
855 which classes, methods, code paths, etc are actually executed. This
856 is most useful when running a test suite to determine whether the
857 tests actually cover the code they're expected to.
859 More information about how to use the coverage profiler is available
860 on the \fBmono\-profilers\fR(1) page, under the \fBCOVERAGE
863 The AOT profiler can help improve startup performance by logging
864 which generic instantiations are used by a program, which the AOT
865 compiler can then use to compile those instantiations ahead of time
866 so that they won't have to be JIT compiled at startup.
868 More information about how to use the AOT profiler is available on
869 the \fBmono\-profilers\fR(1) page, under the \fBAOT PROFILER\fR
872 Custom profiler modules can be loaded in exactly the same way as the
873 standard modules that ship with Mono. They can also access the same
874 profiler API to gather all kinds of information about the code being
877 For example, to use a third-party profiler called \fBcustom\fR, you
878 would load it like this:
882 mono --profile=custom program.exe
886 You could also pass arguments to it:
890 mono --profile=custom:arg1,arg2=arg3 program.exe
894 In the above example, Mono will load the profiler from the shared
895 library called \fIlibmono\-profiler\-custom.so\fR (name varies based
896 on platform, e.g., \fIlibmono\-profiler\-custom.dylib\fR on OS X).
897 This profiler module must be on your dynamic linker library path
898 (\fBLD_LIBRARY_PATH\fR on most systems, \fBDYLD_LIBRARY_PATH\fR on
901 For a sample of how to write your own custom profiler, look at the
902 \fIsamples/profiler/sample.c\fR file in the Mono source tree.
904 To debug managed applications, you can use the
906 command, a command line debugger.
908 It is possible to obtain a stack trace of all the active threads in
909 Mono by sending the QUIT signal to Mono, you can do this from the
910 command line, like this:
916 Where pid is the Process ID of the Mono process you want to examine.
917 The process will continue running afterwards, but its state is not
921 this is a last-resort mechanism for debugging applications and should
922 not be used to monitor or probe a production application. The
923 integrity of the runtime after sending this signal is not guaranteed
924 and the application might crash or terminate at any given point
927 The \fB--debug=casts\fR option can be used to get more detailed
928 information for Invalid Cast operations, it will provide information
929 about the types involved.
931 You can use the MONO_LOG_LEVEL and MONO_LOG_MASK environment variables
932 to get verbose debugging output about the execution of your
933 application within Mono.
937 environment variable if set, the logging level is changed to the set
938 value. Possible values are "error", "critical", "warning", "message",
939 "info", "debug". The default value is "error". Messages with a logging
940 level greater then or equal to the log level will be printed to
943 Use "info" to track the dynamic loading of assemblies.
948 environment variable to limit the extent of the messages you get:
949 If set, the log mask is changed to the set value. Possible values are
950 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
951 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
952 "security" (e.g. Moonlight CoreCLR support), "threadpool" (thread pool generic),
953 "io-selector" (async socket operations), "io-layer" (I/O layer - processes, files,
954 sockets, events, semaphores, mutexes and handles), "io-layer-process",
955 "io-layer-file", "io-layer-socket", "io-layer-event", "io-layer-semaphore",
956 "io-layer-mutex", "io-layer-handle" and "all".
957 The default value is "all". Changing the mask value allows you to display only
958 messages for a certain component. You can use multiple masks by comma
959 separating them. For example to see config file messages and assembly loader
960 messages set you mask to "asm,cfg".
962 The following is a common use to track down problems with P/Invoke:
965 $ MONO_LOG_LEVEL="debug" MONO_LOG_MASK="dll" mono glue.exe
969 .SH DEBUGGING WITH LLDB
970 If you are using LLDB, you can use the
972 script to print some internal data structures with it. To use this,
977 command script import $PREFIX/lib/mono/lldb/mono.py
980 Where $PREFIX is the prefix value that you used when you configured
981 Mono (typically /usr).
983 Once this is done, then you can inspect some Mono Runtime data structures,
988 (MonoMethod *) $0 = 0x05026ac0 [mscorlib]System.OutOfMemoryException:.ctor()
991 Mono's XML serialization engine by default will use a reflection-based
992 approach to serialize which might be slow for continuous processing
993 (web service applications). The serialization engine will determine
994 when a class must use a hand-tuned serializer based on a few
995 parameters and if needed it will produce a customized C# serializer
996 for your types at runtime. This customized serializer then gets
997 dynamically loaded into your application.
999 You can control this with the MONO_XMLSERIALIZER_THS environment
1002 The possible values are
1004 to disable the use of a C# customized
1005 serializer, or an integer that is the minimum number of uses before
1006 the runtime will produce a custom serializer (0 will produce a
1007 custom serializer on the first access, 50 will produce a serializer on
1008 the 50th use). Mono will fallback to an interpreted serializer if the
1009 serializer generation somehow fails. This behavior can be disabled
1010 by setting the option
1012 (for example: MONO_XMLSERIALIZER_THS=0,nofallback).
1013 .SH ENVIRONMENT VARIABLES
1016 Turns off the garbage collection in Mono. This should be only used
1017 for debugging purposes
1020 (Also \fBhttp_proxy\fR) If set, web requests using the Mono
1021 Class Library will be automatically proxied through the given URL.
1022 Not supported on Windows, Mac OS, iOS or Android. See also \fBNO_PROXY\fR.
1025 When Mono is compiled with LLVM support, this instructs the runtime to
1026 stop using LLVM after the specified number of methods are JITed.
1027 This is a tool used in diagnostics to help isolate problems in the
1028 code generation backend. For example \fBLLVM_COUNT=10\fR would only
1029 compile 10 methods with LLVM and then switch to the Mono JIT engine.
1030 \fBLLVM_COUNT=0\fR would disable the LLVM engine altogether.
1032 \fBMONO_ASPNET_INHIBIT_SETTINGSMAP\fR
1033 Mono contains a feature which allows modifying settings in the .config files shipped
1034 with Mono by using config section mappers. The mappers and the mapping rules are
1035 defined in the $prefix/etc/mono/2.0/settings.map file and, optionally, in the
1036 settings.map file found in the top-level directory of your ASP.NET application.
1037 Both files are read by System.Web on application startup, if they are found at the
1038 above locations. If you don't want the mapping to be performed you can set this
1039 variable in your environment before starting the application and no action will
1042 \fBMONO_ASPNET_WEBCONFIG_CACHESIZE\fR
1043 Mono has a cache of ConfigSection objects for speeding up WebConfigurationManager
1044 queries. Its default size is 100 items, and when more items are needed, cache
1045 evictions start happening. If evictions are too frequent this could impose
1046 unnecessary overhead, which could be avoided by using this environment variable
1047 to set up a higher cache size (or to lower memory requirements by decreasing it).
1049 \fBMONO_CAIRO_DEBUG_DISPOSE\fR
1050 If set, causes Mono.Cairo to collect stack traces when objects are allocated,
1051 so that the finalization/Dispose warnings include information about the
1055 If set, this variable overrides the default system configuration directory
1056 ($PREFIX/etc). It's used to locate machine.config file.
1059 Sets the style of COM interop. If the value of this variable is "MS"
1060 Mono will use string marhsalling routines from the liboleaut32 for the
1061 BSTR type library, any other values will use the mono-builtin BSTR
1065 If set, this variable overrides the default runtime configuration file
1066 ($PREFIX/etc/mono/config). The --config command line options overrides the
1067 environment variable.
1070 Override the automatic cpu detection mechanism. Currently used only on arm.
1071 The format of the value is as follows:
1077 where V is the architecture number 4, 5, 6, 7 and the options can be currently be
1078 "thumb" or "thumb2". Example:
1081 MONO_CPU_ARCH="armv4 thumb" mono ...
1085 \fBMONO_ARM_FORCE_SOFT_FLOAT\fR
1086 When Mono is built with a soft float fallback on ARM and this variable is set to
1087 "1", Mono will always emit soft float code, even if a VFP unit is
1090 \fBMONO_DARWIN_WATCHER_MAXFDS\fR
1091 This is a debugging aid used to force limits on the FileSystemWatcher
1092 implementation in Darwin. There is no limit by default.
1094 \fBMONO_DISABLE_AIO\fR
1095 If set, tells mono NOT to attempt using native asynchronous I/O services. In
1096 that case, a default select/poll implementation is used. Currently only epoll()
1099 \fBMONO_DISABLE_MANAGED_COLLATION\fR
1100 If this environment variable is `yes', the runtime uses unmanaged
1101 collation (which actually means no culture-sensitive collation). It
1102 internally disables managed collation functionality invoked via the
1103 members of System.Globalization.CompareInfo class. Collation is
1106 \fBMONO_DISABLE_SHARED_AREA\fR
1107 Unix only: If set, disable usage of shared memory for exposing
1108 performance counters. This means it will not be possible to both
1109 externally read performance counters from this processes or read
1110 those of external processes.
1113 When set, enables the use of a fully managed DNS resolver instead of the
1114 regular libc functions. This resolver performs much better when multiple
1115 queries are run in parallel.
1117 Note that /etc/nsswitch.conf will be ignored.
1119 \fBMONO_EGD_SOCKET\fR
1120 For platforms that do not otherwise have a way of obtaining random bytes
1121 this can be set to the name of a file system socket on which an egd or
1122 prngd daemon is listening.
1124 \fBMONO_ENABLE_COOP\fR
1125 This makes the Mono runtime and the SGen garbage collector run in cooperative
1126 mode as opposed to run on preemptive mode. Preemptive mode is the mode
1127 that Mono has used historically, going back to the Boehm days, where the
1128 garbage collector would run at any point and suspend execution of all
1129 threads as required to perform a garbage collection. The cooperative mode
1130 on the other hand requires the cooperation of all threads to stop at a
1131 safe point. This makes for an easier to debug garbage collector. As
1132 of Mono 4.3.0 it is a work in progress, and while it works, it has not
1133 been used extensively. This option enabled the feature and allows us to
1134 find spots that need to be tuned for this mode of operation. Alternatively,
1135 this mode can be enabled at compile time by using the --with-cooperative-gc
1136 flag when calling configure.
1138 \fBMONO_ENV_OPTIONS\fR
1139 This environment variable allows you to pass command line arguments to
1140 a Mono process through the environment. This is useful for example
1141 to force all of your Mono processes to use LLVM or SGEN without having
1142 to modify any launch scripts.
1144 \fBMONO_SDB_ENV_OPTIONS\fR
1145 Used to pass extra options to the debugger agent in the runtime, as they were passed
1146 using --debugger-agent=.
1148 \fBMONO_EVENTLOG_TYPE\fR
1149 Sets the type of event log provider to use (for System.Diagnostics.EventLog).
1151 Possible values are:
1156 Persists event logs and entries to the local file system.
1158 The directory in which to persist the event logs, event sources and entries
1159 can be specified as part of the value.
1161 If the path is not explicitly set, it defaults to "/var/lib/mono/eventlog"
1162 on unix and "%APPDATA%\mono\eventlog" on Windows.
1167 Uses the native win32 API to write events and registers event logs and
1168 event sources in the registry. This is only available on Windows.
1170 On Unix, the directory permission for individual event log and event source
1171 directories is set to 777 (with +t bit) allowing everyone to read and write
1172 event log entries while only allowing entries to be deleted by the user(s)
1177 Silently discards any events.
1180 The default is "null" on Unix (and versions of Windows before NT), and
1181 "win32" on Windows NT (and higher).
1184 \fBMONO_EXTERNAL_ENCODINGS\fR
1185 If set, contains a colon-separated list of text encodings to try when
1186 turning externally-generated text (e.g. command-line arguments or
1187 filenames) into Unicode. The encoding names come from the list
1188 provided by iconv, and the special case "default_locale" which refers
1189 to the current locale's default encoding.
1191 When reading externally-generated text strings UTF-8 is tried first,
1192 and then this list is tried in order with the first successful
1193 conversion ending the search. When writing external text (e.g. new
1194 filenames or arguments to new processes) the first item in this list
1195 is used, or UTF-8 if the environment variable is not set.
1197 The problem with using MONO_EXTERNAL_ENCODINGS to process your
1198 files is that it results in a problem: although its possible to get
1199 the right file name it is not necessarily possible to open the file.
1200 In general if you have problems with encodings in your filenames you
1201 should use the "convmv" program.
1203 \fBMONO_GC_PARAMS\fR
1204 When using Mono with the SGen garbage collector this variable controls
1205 several parameters of the collector. The variable's value is a comma
1206 separated list of words.
1210 \fBmax-heap-size=\fIsize\fR
1211 Sets the maximum size of the heap. The size is specified in bytes and must
1212 be a power of two. The suffixes `k', `m' and `g' can be used to
1213 specify kilo-, mega- and gigabytes, respectively. The limit is the sum
1214 of the nursery, major heap and large object heap. Once the limit is reached
1215 the application will receive OutOfMemoryExceptions when trying to allocate.
1216 Not the full extent of memory set in max-heap-size could be available to
1217 satisfy a single allocation due to internal fragmentation. By default heap
1218 limits is disabled and the GC will try to use all available memory.
1220 \fBnursery-size=\fIsize\fR
1221 Sets the size of the nursery. The size is specified in bytes and must
1222 be a power of two. The suffixes `k', `m' and `g' can be used to
1223 specify kilo-, mega- and gigabytes, respectively. The nursery is the
1224 first generation (of two). A larger nursery will usually speed up the
1225 program but will obviously use more memory. The default nursery size
1228 \fBmajor=\fIcollector\fR
1229 Specifies which major collector to use.
1230 Options are `marksweep' for the Mark&Sweep collector, `marksweep-conc'
1231 for concurrent Mark&Sweep and `marksweep-conc-par' for parallel and
1232 concurrent Mark&Sweep. The concurrent Mark&Sweep collector is the default.
1234 \fBmode=balanced|throughput|pause\fR[:\fImax-pause\fR]
1235 Specifies what should be the garbage collector's target. The `throughput'
1236 mode aims to reduce time spent in the garbage collector and improve
1237 application speed, the `pause' mode aims to keep pause times to a minimum
1238 and it receives the argument \fImax-pause\fR which specifies the maximum
1239 pause time in milliseconds that is acceptable and the `balanced' mode
1240 which is a general purpose optimal mode.
1242 \fBsoft-heap-limit=\fIsize\fR
1243 Once the heap size gets larger than this size, ignore what the default
1244 major collection trigger metric says and only allow four nursery size's
1245 of major heap growth between major collections.
1247 \fBevacuation-threshold=\fIthreshold\fR
1248 Sets the evacuation threshold in percent. This option is only available
1249 on the Mark&Sweep major collectors. The value must be an
1250 integer in the range 0 to 100. The default is 66. If the sweep phase of
1251 the collection finds that the occupancy of a specific heap block type is
1252 less than this percentage, it will do a copying collection for that block
1253 type in the next major collection, thereby restoring occupancy to close
1254 to 100 percent. A value of 0 turns evacuation off.
1256 \fB(no-)lazy-sweep\fR
1257 Enables or disables lazy sweep for the Mark&Sweep collector. If
1258 enabled, the sweeping of individual major heap blocks is done
1259 piecemeal whenever the need arises, typically during nursery
1260 collections. Lazy sweeping is enabled by default.
1262 \fB(no-)concurrent-sweep\fR
1263 Enables or disables concurrent sweep for the Mark&Sweep collector. If
1264 enabled, the iteration of all major blocks to determine which ones can
1265 be freed and which ones have to be kept and swept, is done
1266 concurrently with the running program. Concurrent sweeping is enabled
1269 \fBstack-mark=\fImark-mode\fR
1270 Specifies how application threads should be scanned. Options are
1271 `precise` and `conservative`. Precise marking allow the collector
1272 to know what values on stack are references and what are not.
1273 Conservative marking threats all values as potentially references
1274 and leave them untouched. Precise marking reduces floating garbage
1275 and can speed up nursery collection and allocation rate, it has
1276 the downside of requiring a significant extra memory per compiled
1277 method. The right option, unfortunately, requires experimentation.
1279 \fBsave-target-ratio=\fIratio\fR
1280 Specifies the target save ratio for the major collector. The collector
1281 lets a given amount of memory to be promoted from the nursery due to
1282 minor collections before it triggers a major collection. This amount
1283 is based on how much memory it expects to free. It is represented as
1284 a ratio of the size of the heap after a major collection.
1285 Valid values are between 0.1 and 2.0. The default is 0.5.
1286 Smaller values will keep the major heap size smaller but will trigger
1287 more major collections. Likewise, bigger values will use more memory
1288 and result in less frequent major collections.
1289 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1291 \fBdefault-allowance-ratio=\fIratio\fR
1292 Specifies the default allocation allowance when the calculated size
1293 is too small. The allocation allowance is how much memory the collector
1294 let be promoted before triggered a major collection.
1295 It is a ratio of the nursery size.
1296 Valid values are between 1.0 and 10.0. The default is 4.0.
1297 Smaller values lead to smaller heaps and more frequent major collections.
1298 Likewise, bigger values will allow the heap to grow faster but use
1299 more memory when it reaches a stable size.
1300 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1302 \fBminor=\fIminor-collector\fR
1303 Specifies which minor collector to use. Options are `simple' which
1304 promotes all objects from the nursery directly to the old generation,
1305 `simple-par' which has same promotion behavior as `simple' but using
1306 multiple workers and `split' which lets objects stay longer on the nursery
1309 \fBalloc-ratio=\fIratio\fR
1310 Specifies the ratio of memory from the nursery to be use by the alloc space.
1311 This only can only be used with the split minor collector.
1312 Valid values are integers between 1 and 100. Default is 60.
1314 \fBpromotion-age=\fIage\fR
1315 Specifies the required age of an object must reach inside the nursery before
1316 been promoted to the old generation. This only can only be used with the
1317 split minor collector.
1318 Valid values are integers between 1 and 14. Default is 2.
1320 \fB(no-)cementing\fR
1321 Enables or disables cementing. This can dramatically shorten nursery
1322 collection times on some benchmarks where pinned objects are referred
1323 to from the major heap.
1325 \fBallow-synchronous-major\fR
1326 This forbids the major collector from performing synchronous major collections.
1327 The major collector might want to do a synchronous collection due to excessive
1328 fragmentation. Disabling this might trigger OutOfMemory error in situations that
1329 would otherwise not happen.
1334 When using Mono with the SGen garbage collector this environment
1335 variable can be used to turn on various debugging features of the
1336 collector. The value of this variable is a comma separated list of
1337 words. Do not use these options in production.
1342 Sets the debug level to the specified number.
1344 \fBprint-allowance\fR
1345 After each major collection prints memory consumption for before and
1346 after the collection and the allowance for the minor collector, i.e. how
1347 much the heap is allowed to grow from minor collections before the next
1348 major collection is triggered.
1351 Gathers statistics on the classes whose objects are pinned in the
1352 nursery and for which global remset entries are added. Prints those
1353 statistics when shutting down.
1355 \fBcollect-before-allocs\fR
1357 \fBcheck-remset-consistency\fR
1358 This performs a remset consistency check at various opportunities, and
1359 also clears the nursery at collection time, instead of the default,
1360 when buffers are allocated (clear-at-gc). The consistency check
1361 ensures that there are no major to minor references that are not on
1362 the remembered sets.
1364 \fBmod-union-consistency-check\fR
1365 Checks that the mod-union cardtable is consistent before each
1366 finishing major collection pause. This check is only applicable to
1367 concurrent major collectors.
1369 \fBcheck-mark-bits\fR
1370 Checks that mark bits in the major heap are consistent at the end of
1371 each major collection. Consistent mark bits mean that if an object is
1372 marked, all objects that it had references to must also be marked.
1374 \fBcheck-nursery-pinned\fR
1375 After nursery collections, and before starting concurrent collections,
1376 check whether all nursery objects are pinned, or not pinned -
1377 depending on context. Does nothing when the split nursery collector
1380 \fBxdomain-checks\fR
1381 Performs a check to make sure that no references are left to an
1384 \fBclear-at-tlab-creation\fR
1385 Clears the nursery incrementally when the thread local allocation
1386 buffers (TLAB) are created. The default setting clears the whole
1389 \fBdebug-clear-at-tlab-creation\fR
1390 Clears the nursery incrementally when the thread local allocation
1391 buffers (TLAB) are created, but at GC time fills it with the byte
1392 `0xff`, which should result in a crash more quickly if
1393 `clear-at-tlab-creation` doesn't work properly.
1396 This clears the nursery at GC time instead of doing it when the thread
1397 local allocation buffer (TLAB) is created. The default is to clear
1398 the nursery at TLAB creation time.
1401 Don't do minor collections. If the nursery is full, a major collection
1402 is triggered instead, unless it, too, is disabled.
1405 Don't do major collections.
1407 \fBconservative-stack-mark\fR
1408 Forces the GC to scan the stack conservatively, even if precise
1409 scanning is available.
1411 \fBno-managed-allocator\fR
1412 Disables the managed allocator.
1414 \fBcheck-scan-starts\fR
1415 If set, does a plausibility check on the scan_starts before and after each collection
1417 \fBverify-nursery-at-minor-gc\fR
1418 If set, does a complete object walk of the nursery at the start of each minor collection.
1420 \fBdump-nursery-at-minor-gc\fR
1421 If set, dumps the contents of the nursery at the start of each minor collection. Requires
1422 verify-nursery-at-minor-gc to be set.
1424 \fBheap-dump=\fIfile\fR
1425 Dumps the heap contents to the specified file. To visualize the
1426 information, use the mono-heapviz tool.
1428 \fBbinary-protocol=\fIfile\fR
1429 Outputs the debugging output to the specified file. For this to
1430 work, Mono needs to be compiled with the BINARY_PROTOCOL define on
1431 sgen-gc.c. You can then use this command to explore the output
1433 sgen-grep-binprot 0x1234 0x5678 < file
1436 \fBnursery-canaries\fR
1437 If set, objects allocated in the nursery are suffixed with a canary (guard)
1438 word, which is checked on each minor collection. Can be used to detect/debug
1439 heap corruption issues.
1442 \fBdo-not-finalize(=\fIclasses\fB)\fR
1443 If enabled, finalizers will not be run. Everything else will be
1444 unaffected: finalizable objects will still be put into the
1445 finalization queue where they survive until they're scheduled to
1446 finalize. Once they're not in the queue anymore they will be
1447 collected regularly. If a list of comma-separated class names is
1448 given, only objects from those classes will not be finalized.
1451 \fBlog-finalizers\fR
1452 Log verbosely around the finalization process to aid debugging.
1456 \fBMONO_GAC_PREFIX\fR
1457 Provides a prefix the runtime uses to look for Global Assembly Caches.
1458 Directories are separated by the platform path separator (colons on
1459 unix). MONO_GAC_PREFIX should point to the top directory of a prefixed
1460 install. Or to the directory provided in the gacutil /gacdir command. Example:
1461 .B /home/username/.mono:/usr/local/mono/
1464 Enables some filename rewriting support to assist badly-written
1465 applications that hard-code Windows paths. Set to a colon-separated
1466 list of "drive" to strip drive letters, or "case" to do
1467 case-insensitive file matching in every directory in a path. "all"
1468 enables all rewriting methods. (Backslashes are always mapped to
1469 slashes if this variable is set to a valid option).
1472 For example, this would work from the shell:
1475 MONO_IOMAP=drive:case
1479 If you are using mod_mono to host your web applications, you can use
1482 directive instead, like this:
1485 MonoIOMAP <appalias> all
1488 See mod_mono(8) for more details.
1491 When Mono is using the LLVM code generation backend you can use this
1492 environment variable to pass code generation options to the LLVM
1495 \fBMONO_MANAGED_WATCHER\fR
1496 If set to "disabled", System.IO.FileSystemWatcher will use a file watcher
1497 implementation which silently ignores all the watching requests.
1498 If set to any other value, System.IO.FileSystemWatcher will use the default
1499 managed implementation (slow). If unset, mono will try to use inotify, FAM,
1500 Gamin, kevent under Unix systems and native API calls on Windows, falling
1501 back to the managed implementation on error.
1503 \fBMONO_MESSAGING_PROVIDER\fR
1504 Mono supports a plugin model for its implementation of System.Messaging making
1505 it possible to support a variety of messaging implementations (e.g. AMQP, ActiveMQ).
1506 To specify which messaging implementation is to be used the evironement variable
1507 needs to be set to the full class name for the provider. E.g. to use the RabbitMQ based
1508 AMQP implementation the variable should be set to:
1511 Mono.Messaging.RabbitMQ.RabbitMQMessagingProvider,Mono.Messaging.RabbitMQ
1514 If set causes the mono process to be bound to a single processor. This may be
1515 useful when debugging or working around race conditions.
1518 Disable inlining of thread local accesses. Try setting this if you get a segfault
1519 early on in the execution of mono.
1522 Provides a search path to the runtime where to look for library
1523 files. This is a tool convenient for debugging applications, but
1524 should not be used by deployed applications as it breaks the assembly
1525 loader in subtle ways.
1527 Directories are separated by the platform path separator (colons on unix). Example:
1528 .B /home/username/lib:/usr/local/mono/lib
1530 Relative paths are resolved based on the launch-time current directory.
1532 Alternative solutions to MONO_PATH include: installing libraries into
1533 the Global Assembly Cache (see gacutil(1)) or having the dependent
1534 libraries side-by-side with the main executable.
1536 For a complete description of recommended practices for application
1538 http://www.mono-project.com/docs/getting-started/application-deployment/
1540 \fBMONO_SHARED_DIR\fR
1541 If set its the directory where the ".wapi" handle state is stored.
1542 This is the directory where the Windows I/O Emulation layer stores its
1543 shared state data (files, events, mutexes, pipes). By default Mono
1544 will store the ".wapi" directory in the users's home directory.
1546 \fBMONO_SHARED_HOSTNAME\fR
1547 Uses the string value of this variable as a replacement for the host name when
1548 creating file names in the ".wapi" directory. This helps if the host name of
1549 your machine is likely to be changed when a mono application is running or if
1550 you have a .wapi directory shared among several different computers.
1552 Mono typically uses the hostname to create the files that are used to
1553 share state across multiple Mono processes. This is done to support
1554 home directories that might be shared over the network.
1556 \fBMONO_STRICT_IO_EMULATION\fR
1557 If set, extra checks are made during IO operations. Currently, this
1558 includes only advisory locks around file writes.
1561 The name of the theme to be used by Windows.Forms. Available themes today
1562 include "clearlooks", "nice" and "win32".
1564 The default is "win32".
1566 \fBMONO_TLS_SESSION_CACHE_TIMEOUT\fR
1567 The time, in seconds, that the SSL/TLS session cache will keep it's entry to
1568 avoid a new negotiation between the client and a server. Negotiation are very
1569 CPU intensive so an application-specific custom value may prove useful for
1570 small embedded systems.
1572 The default is 180 seconds.
1574 \fBMONO_THREADS_PER_CPU\fR
1575 The minimum number of threads in the general threadpool will be
1576 MONO_THREADS_PER_CPU * number of CPUs. The default value for this
1579 \fBMONO_XMLSERIALIZER_THS\fR
1580 Controls the threshold for the XmlSerializer to produce a custom
1581 serializer for a given class instead of using the Reflection-based
1582 interpreter. The possible values are `no' to disable the use of a
1583 custom serializer or a number to indicate when the XmlSerializer
1584 should start serializing. The default value is 50, which means that
1585 the a custom serializer will be produced on the 50th use.
1587 \fBMONO_X509_REVOCATION_MODE\fR
1588 Sets the revocation mode used when validating a X509 certificate chain (https,
1589 ftps, smtps...). The default is 'nocheck', which performs no revocation check
1590 at all. The other possible values are 'offline', which performs CRL check (not
1591 implemented yet) and 'online' which uses OCSP and CRL to verify the revocation
1592 status (not implemented yet).
1595 (Also \fBno_proxy\fR) If both \fBHTTP_PROXY\fR and \fBNO_PROXY\fR are
1596 set, \fBNO_PROXY\fR will be treated as a comma-separated list of "bypass" domains
1597 which will not be sent through the proxy. Domains in \fBNO_PROXY\fR may contain
1598 wildcards, as in "*.mono-project.com" or "build????.local". Not supported on
1599 Windows, Mac OS, iOS or Android.
1600 .SH ENVIRONMENT VARIABLES FOR DEBUGGING
1602 \fBMONO_ASPNET_NODELETE\fR
1603 If set to any value, temporary source files generated by ASP.NET support
1604 classes will not be removed. They will be kept in the user's temporary
1608 If set, enables some features of the runtime useful for debugging.
1609 This variable should contain a comma separated list of debugging options.
1610 Currently, the following options are supported:
1614 \fBalign-small-structs\fR
1615 Enables small structs alignment to 4/8 bytes.
1617 \fBarm-use-fallback-tls\fR
1618 When this option is set on ARM, a fallback TLS will be used instead
1619 of the default fast TLS.
1621 \fBbreak-on-unverified\fR
1622 If this variable is set, when the Mono VM runs into a verification
1623 problem, instead of throwing an exception it will break into the
1624 debugger. This is useful when debugging verifier problems
1627 This option can be used to get more detailed information from
1628 InvalidCast exceptions, it will provide information about the types
1631 \fBcheck-pinvoke-callconv\fR
1632 This option causes the runtime to check for calling convention
1633 mismatches when using pinvoke, i.e. mixing cdecl/stdcall. It only
1634 works on windows. If a mismatch is detected, an
1635 ExecutionEngineException is thrown.
1637 \fBcollect-pagefault-stats\fR
1638 Collects information about pagefaults. This is used internally to
1639 track the number of page faults produced to load metadata. To display
1640 this information you must use this option with "--stats" command line
1643 \fBdebug-domain-unload\fR
1644 When this option is set, the runtime will invalidate the domain memory
1645 pool instead of destroying it.
1647 \fBdisable_omit_fp\fR
1648 Disables a compiler optimization where the frame pointer is omitted
1649 from the stack. This optimization can interact badly with debuggers.
1651 \fBdont-free-domains\fR
1652 This is an Optimization for multi-AppDomain applications (most
1653 commonly ASP.NET applications). Due to internal limitations Mono,
1654 Mono by default does not use typed allocations on multi-appDomain
1655 applications as they could leak memory when a domain is unloaded.
1657 Although this is a fine default, for applications that use more than
1658 on AppDomain heavily (for example, ASP.NET applications) it is worth
1659 trading off the small leaks for the increased performance
1660 (additionally, since ASP.NET applications are not likely going to
1661 unload the application domains on production systems, it is worth
1662 using this feature).
1664 \fBdyn-runtime-invoke\fR
1665 Instructs the runtime to try to use a generic runtime-invoke wrapper
1666 instead of creating one invoke wrapper.
1668 \fBexplicit-null-checks\fR
1669 Makes the JIT generate an explicit NULL check on variable dereferences
1670 instead of depending on the operating system to raise a SIGSEGV or
1671 another form of trap event when an invalid memory location is
1675 Equivalent to setting the \fBMONO_XDEBUG\fR variable, this emits
1676 symbols into a shared library as the code is JITed that can be loaded
1677 into GDB to inspect symbols.
1679 \fBgen-seq-points\fR
1680 Automatically generates sequence points where the
1681 IL stack is empty. These are places where the debugger can set a
1684 \fBno-compact-seq-points\fR
1685 Unless the option is used, the runtime generates sequence points data that
1686 maps native offsets to IL offsets. Sequence point data is used to
1687 display IL offset in stacktraces. Stacktraces with IL offsets can be
1688 symbolicated using mono-symbolicate tool.
1691 Captures the interrupt signal (Control-C) and displays a stack trace
1692 when pressed. Useful to find out where the program is executing at a
1693 given point. This only displays the stack trace of a single thread.
1696 Instructs the runtime to initialize the stack with
1697 some known values (0x2a on x86-64) at the start of a method to assist
1698 in debuggin the JIT engine.
1700 \fBkeep-delegates\fR
1701 This option will leak delegate trampolines that are no longer
1702 referenced as to present the user with more information about a
1703 delegate misuse. Basically a delegate instance might be created,
1704 passed to unmanaged code, and no references kept in managed code,
1705 which will garbage collect the code. With this option it is possible
1706 to track down the source of the problems.
1708 \fBno-gdb-backtrace\fR
1709 This option will disable the GDB backtrace emitted by the runtime
1710 after a SIGSEGV or SIGABRT in unmanaged code.
1712 \fBpartial-sharing\fR
1713 When this option is set, the runtime can share generated code between
1714 generic types effectively reducing the amount of code generated.
1716 \fBreverse-pinvoke-exceptions
1717 This option will cause mono to abort with a descriptive message when
1718 during stack unwinding after an exception it reaches a native stack
1719 frame. This happens when a managed delegate is passed to native code,
1720 and the managed delegate throws an exception. Mono will normally try
1721 to unwind the stack to the first (managed) exception handler, and it
1722 will skip any native stack frames in the process. This leads to
1723 undefined behaviour (since mono doesn't know how to process native
1724 frames), leaks, and possibly crashes too.
1726 \fBsingle-imm-size\fR
1727 This guarantees that each time managed code is compiled the same
1728 instructions and registers are used, regardless of the size of used
1731 \fBsoft-breakpoints\fR
1732 This option allows using single-steps and breakpoints in hardware
1733 where we cannot do it with signals.
1735 \fBsuspend-on-native-crash\fR
1736 This option will suspend the program when a native crash occurs (SIGSEGV, SIGILL, ...).
1737 This is useful for debugging crashes which do not happen under gdb,
1738 since a live process contains more information than a core file.
1740 \fBsuspend-on-sigsegv\fR
1741 Same as \fBsuspend-on-native-crash\fR.
1743 \fBsuspend-on-exception\fR
1744 This option will suspend the program when an exception occurs.
1746 \fBsuspend-on-unhandled\fR
1747 This option will suspend the program when an unhandled exception occurs.
1751 \fBMONO_LOG_LEVEL\fR
1752 The logging level, possible values are `error', `critical', `warning',
1753 `message', `info' and `debug'. See the DEBUGGING section for more
1757 Controls the domain of the Mono runtime that logging will apply to.
1758 If set, the log mask is changed to the set value. Possible values are
1759 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1760 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1761 "security" (e.g. Moonlight CoreCLR support) and "all".
1762 The default value is "all". Changing the mask value allows you to display only
1763 messages for a certain component. You can use multiple masks by comma
1764 separating them. For example to see config file messages and assembly loader
1765 messages set you mask to "asm,cfg".
1768 Controls where trace log messages are written. If not set then the messages go to stdout.
1769 If set, the string either specifies a path to a file that will have messages appended to
1770 it, or the string "syslog" in which case the messages will be written to the system log.
1771 Under Windows, this is simulated by writing to a file called "mono.log".
1772 \fBMONO_LOG_HEADER\fR
1773 Controls whether trace log messages not directed to syslog have the id, timestamp, and
1774 pid as the prefix to the log message. To enable a header this environment variable need
1778 Used for runtime tracing of method calls. The format of the comma separated
1787 disabled Trace output off upon start.
1790 You can toggle trace output on/off sending a SIGUSR2 signal to the program.
1792 \fBMONO_TRACE_LISTENER\fR
1793 If set, enables the System.Diagnostics.DefaultTraceListener, which will
1794 print the output of the System.Diagnostics Trace and Debug classes.
1795 It can be set to a filename, and to Console.Out or Console.Error to display
1796 output to standard output or standard error, respectively. If it's set to
1797 Console.Out or Console.Error you can append an optional prefix that will
1798 be used when writing messages like this: Console.Error:MyProgramName.
1799 See the System.Diagnostics.DefaultTraceListener documentation for more
1802 \fBMONO_WCF_TRACE\fR
1803 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.
1805 \fBMONO_XEXCEPTIONS\fR
1806 This throws an exception when a X11 error is encountered; by default a
1807 message is displayed but execution continues
1809 \fBMONO_XMLSERIALIZER_DEBUG\fR
1810 Set this value to 1 to prevent the serializer from removing the
1811 temporary files that are created for fast serialization; This might
1812 be useful when debugging.
1815 This is used in the System.Windows.Forms implementation when running
1816 with the X11 backend. This is used to debug problems in Windows.Forms
1817 as it forces all of the commands send to X11 server to be done
1818 synchronously. The default mode of operation is asynchronous which
1819 makes it hard to isolate the root of certain problems.
1822 When the the MONO_XDEBUG env var is set, debugging info for JITted
1823 code is emitted into a shared library, loadable into gdb. This enables,
1824 for example, to see managed frame names on gdb backtraces.
1826 \fBMONO_VERBOSE_METHOD\fR
1827 Enables the maximum JIT verbosity for the specified method. This is
1828 very helpfull to diagnose a miscompilation problems of a specific
1831 \fBMONO_JIT_DUMP_METHOD\fR
1832 Enables sending of the JITs intermediate representation for a specified
1833 method to the IdealGraphVisualizer tool.
1835 \fBMONO_VERBOSE_HWCAP\fR
1836 If set, makes the JIT output information about detected CPU features
1837 (such as SSE, CMOV, FCMOV, etc) to stdout.
1839 \fBMONO_CONSERVATIVE_HWCAP\fR
1840 If set, the JIT will not perform any hardware capability detection. This
1841 may be useful to pinpoint the cause of JIT issues. This is the default
1842 when Mono is built as an AOT cross compiler, so that the generated code
1843 will run on most hardware.
1845 If you want to use Valgrind, you will find the file `mono.supp'
1846 useful, it contains the suppressions for the GC which trigger
1847 incorrect warnings. Use it like this:
1849 valgrind --suppressions=mono.supp mono ...
1852 On some platforms, Mono can expose a set of DTrace probes (also known
1853 as user-land statically defined, USDT Probes).
1855 They are defined in the file `mono.d'.
1857 .B ves-init-begin, ves-init-end
1859 Begin and end of runtime initialization.
1861 .B method-compile-begin, method-compile-end
1863 Begin and end of method compilation.
1864 The probe arguments are class name, method name and signature,
1865 and in case of method-compile-end success or failure of compilation.
1869 Begin and end of Garbage Collection.
1871 To verify the availability of the probes, run:
1873 dtrace -P mono'$target' -l -c mono
1876 Mono's Ping implementation for detecting network reachability can
1877 create the ICMP packets itself without requiring the system ping
1878 command to do the work. If you want to enable this on Linux for
1879 non-root users, you need to give the Mono binary special permissions.
1881 As root, run this command:
1883 # setcap cap_net_raw=+ep /usr/bin/mono
1886 On Unix assemblies are loaded from the installation lib directory. If you set
1887 `prefix' to /usr, the assemblies will be located in /usr/lib. On
1888 Windows, the assemblies are loaded from the directory where mono and
1891 .B ~/.mono/aot-cache
1893 The directory for the ahead-of-time compiler demand creation
1894 assemblies are located.
1896 .B /etc/mono/config, ~/.mono/config
1898 Mono runtime configuration file. See the mono-config(5) manual page
1899 for more information.
1901 .B ~/.config/.mono/certs, /usr/share/.mono/certs
1903 Contains Mono certificate stores for users / machine. See the certmgr(1)
1904 manual page for more information on managing certificate stores and
1905 the mozroots(1) page for information on how to import the Mozilla root
1906 certificates into the Mono certificate store.
1908 .B ~/.mono/assemblies/ASSEMBLY/ASSEMBLY.config
1910 Files in this directory allow a user to customize the configuration
1911 for a given system assembly, the format is the one described in the
1912 mono-config(5) page.
1914 .B ~/.config/.mono/keypairs, /usr/share/.mono/keypairs
1916 Contains Mono cryptographic keypairs for users / machine. They can be
1917 accessed by using a CspParameters object with DSACryptoServiceProvider
1918 and RSACryptoServiceProvider classes.
1920 .B ~/.config/.isolatedstorage, ~/.local/share/.isolatedstorage, /usr/share/.isolatedstorage
1922 Contains Mono isolated storage for non-roaming users, roaming users and
1923 local machine. Isolated storage can be accessed using the classes from
1924 the System.IO.IsolatedStorage namespace.
1926 .B <assembly>.config
1928 Configuration information for individual assemblies is loaded by the
1929 runtime from side-by-side files with the .config files, see the
1930 http://www.mono-project.com/Config for more information.
1932 .B Web.config, web.config
1934 ASP.NET applications are configured through these files, the
1935 configuration is done on a per-directory basis. For more information
1936 on this subject see the http://www.mono-project.com/Config_system.web
1939 Mailing lists are listed at the
1940 http://www.mono-project.com/community/help/mailing-lists/
1942 http://www.mono-project.com
1945 \fBcertmgr\fR(1), \fBcert-sync\fR(1), \fBcsharp\fR(1),
1946 \fBgacutil\fR(1), \fBmcs\fR(1), \fBmonodis\fR(1),
1947 \fBmono-config\fR(5), \fBmono\-profilers\fR(1),
1948 \fBmprof\-report\fR(1), \fBpdb2mdb\fR(1), \fBxsp\fR(1),
1951 For more information on AOT:
1952 http://www.mono-project.com/docs/advanced/aot/
1954 For ASP.NET-related documentation, see the xsp(1) manual page