3 .\" Copyright 2003 Ximian, Inc.
4 .\" Copyright 2004-2009 Novell, Inc.
6 .\" Miguel de Icaza (miguel@gnu.org)
10 mono \- Mono's ECMA-CLI native code generator (Just-in-Time and Ahead-of-Time)
13 .B mono [options] file [arguments...]
15 .B mono-sgen [options] file [arguments...]
17 \fImono\fP is a runtime implementation of the ECMA Common Language
18 Infrastructure. This can be used to run ECMA and .NET applications.
20 The runtime contains a native code generator that transforms the
21 Common Intermediate Language into native code.
23 The code generator can operate in two modes: just in time compilation
24 (JIT) or ahead of time compilation (AOT). Since code can be
25 dynamically loaded, the runtime environment and the JIT are always
26 present, even if code is compiled ahead of time.
28 The runtime loads the specified
35 is an ECMA assembly. They typically have a .exe or .dll extension.
37 The runtime provides a number of configuration options for running
38 applications, for developing and debugging, and for testing and
39 debugging the runtime itself.
41 The \fImono\fP command uses the Boehm conservative garbage collector
42 while the \fImono-sgen\fP command uses a moving and generational
45 On Unix-based systems, Mono provides a mechanism to emulate the
46 Windows-style file access, this includes providing a case insensitive
47 view of the file system, directory separator mapping (from \\ to /) and
48 stripping the drive letters.
50 This functionality is enabled by setting the
52 environment variable to one of
57 See the description for
59 in the environment variables section for more details.
61 The following options are available:
63 \fB--aot\fR, \fB--aot[=options]\fR
64 This option is used to precompile the CIL code in the specified
65 assembly to native code. The generated code is stored in a file with
66 the extension .so. This file will be automatically picked up by the
67 runtime when the assembly is executed.
69 Ahead-of-Time compilation is most useful if you use it in combination
70 with the -O=all,-shared flag which enables all of the optimizations in
71 the code generator to be performed. Some of those optimizations are
72 not practical for Just-in-Time compilation since they might be very
75 Unlike the .NET Framework, Ahead-of-Time compilation will not generate
76 domain independent code: it generates the same code that the
77 Just-in-Time compiler would produce. Since most applications use a
78 single domain, this is fine. If you want to optimize the generated
79 code for use in multi-domain applications, consider using the
82 This pre-compiles the methods, but the original assembly is still
83 required to execute as this one contains the metadata and exception
84 information which is not available on the generated file. When
85 precompiling code, you might want to compile with all optimizations
86 (-O=all). Pre-compiled code is position independent code.
88 Pre compilation is just a mechanism to reduce startup time, increase
89 code sharing across multiple mono processes and avoid just-in-time
90 compilation program startup costs. The original assembly must still
91 be present, as the metadata is contained there.
93 AOT code typically can not be moved from one computer to another
94 (CPU-specific optimizations that are detected at runtime) so you
95 should not try to move the pre-generated assemblies or package the
96 pre-generated assemblies for deployment.
98 A few options are available as a parameter to the
100 command line option. The options are separated by commas, and more
101 than one can be specified:
105 .I bind-to-runtime-version
107 If specified, forces the generated AOT files to be bound to the
108 runtime version of the compiling Mono. This will prevent the AOT
109 files from being consumed by a different Mono runtime.
111 This is currently an experimental feature as it is not complete.
112 This instructs Mono to precompile code that has historically not been
113 precompiled with AOT.
115 .I outfile=[filename]
116 Instructs the AOT compiler to save the output to the specified file.
119 Instructs the AOT compiler to emit debug symbol information.
121 .I save-temps,keep-temps
122 Instructs the AOT compiler to keep temporary files.
125 This is an experimental option for the AOT compiler to use multiple threads
126 when compiling the methods.
129 Instructs the AOT compiler to not output any debugging information.
131 .I ntrampolines=[number]
132 When compiling in full aot mode, the method trampolines must be precreated
133 in the AOT image. You can add additional method trampolines with this argument.
136 .I nrgctx-trampolines=[number]
137 When compiling in full aot mode, the generic sharing trampolines must be precreated
138 in the AOT image. You can add additional method trampolines with this argument.
141 .I nimt-trampolines=[number]
142 When compiling in full aot mode, the IMT trampolines must be precreated
143 in the AOT image. You can add additional method trampolines with this argument.
146 .I print-skipped-methods
147 If the AOT compiler cannot compile a method for any reason, enabling this flag
148 will output the skipped methods to the console.
151 The AOT compiler will emit a (ELF only) library initializer to automatically
152 register the aot compiled module with the runtime. This is only useful in static
156 Instructs the AOT compiler to output assembly code instead of an object file.
159 This instructs the compiler to generate sequence point checks that
160 allow Mono's soft debugger to debug applications even on systems where
161 it is not possible to set breakpoints or to single step (certain
162 hardware configurations like the cell phones and video gaming
166 Create an ELF object file (.o) which can be statically linked into an executable
167 when embedding the mono runtime. When this option is used, the object file needs to
168 be registered with the embedded runtime using the mono_aot_register_module function
169 which takes as its argument the mono_aot_module_<ASSEMBLY NAME>_info global symbol
170 from the object file:
173 extern void *mono_aot_module_hello_info;
175 mono_aot_register_module (mono_aot_module_hello_info);
180 For more information about AOT, see: http://www.mono-project.com/AOT
183 \fB--attach=[options]\fR
184 Currently the only option supported by this command line argument is
185 \fBdisable\fR which disables the attach functionality.
187 \fB--config filename\fR
188 Load the specified configuration file instead of the default one(s).
189 The default files are /etc/mono/config and ~/.mono/config or the file
190 specified in the MONO_CONFIG environment variable, if set. See the
191 mono-config(5) man page for details on the format of this file.
193 \fB--debugger-agent=[options]\fR
194 This instructs the Mono runtime to
195 start a debugging agent inside the Mono runtime and connect it to a
196 client user interface will control the Mono process.
197 This option is typically used by IDEs, like the MonoDevelop IDE.
200 configuration is specified using one of more of the following options:
204 .I transport=transport_name
206 This is used to specify the transport that the debugger will use to
207 communicate. It must be specified and currently requires this to
212 Use this option to specify the IP address where your debugger client is
217 Specifies the diagnostics log level for
221 Used to specify the file where the log will be stored, it defaults to
225 Defaults to no, with the default option Mono will actively connect to the
226 host/port configured with the \fBaddress\fR option. If you set it to 'y', it
227 instructs the Mono runtime to start debugging in server mode, where Mono
228 actively waits for the debugger front end to connect to the Mono process.
229 Mono will print out to stdout the IP address and port where it is listening.
234 Configures the virtual machine to be better suited for desktop
235 applications. Currently this sets the GC system to avoid expanding
236 the heap as much as possible at the expense of slowing down garbage
240 This is an experimental flag that instructs the Mono runtime to not
241 generate any code at runtime and depend exclusively on the code
242 generated from using mono --aot=full previously. This is useful for
243 platforms that do not permit dynamic code generation.
245 Notice that this feature will abort execution at runtime if a codepath
246 in your program, or Mono's class libraries attempts to generate code
247 dynamically. You should test your software upfront and make sure that
248 you do not use any dynamic features.
250 \fB--gc=boehm\fR, \fB--gc=sgen\fR
251 Selects the Garbage Collector engine for Mono to use, Boehm or SGen.
252 Currently this merely ensures that you are running either the
253 \fImono\fR or \fImono-sgen\fR commands. This flag can be set in the
254 \fBMONO_ENV_OPTIONS\fR environment variable to force all of your child
255 processes to use one particular kind of GC with the Mono runtime.
257 \fB--help\fR, \fB-h\fR
258 Displays usage instructions.
261 If the Mono runtime has been compiled with LLVM support (not available
262 in all configurations), Mono will use the LLVM optimization and code
263 generation engine to JIT or AOT compile.
265 For more information, consult: http://www.mono-project.com/Mono_LLVM
268 When using a Mono that has been compiled with LLVM support, it forces
269 Mono to fallback to its JIT engine and not use the LLVM backend.
271 \fB--optimize=MODE\fR, \fB-O=MODE\fR
272 MODE is a comma separated list of optimizations. They also allow
273 optimizations to be turned off by prefixing the optimization name with
276 In general, Mono has been tuned to use the default set of flags,
277 before using these flags for a deployment setting, you might want to
278 actually measure the benefits of using them.
280 The following optimizations are implemented:
282 all Turn on all optimizations
283 peephole Peephole postpass
284 branch Branch optimizations
285 inline Inline method calls
286 cfold Constant folding
287 consprop Constant propagation
288 copyprop Copy propagation
289 deadce Dead code elimination
290 linears Linear scan global reg allocation
291 cmov Conditional moves [arch-dependency]
292 shared Emit per-domain code
293 sched Instruction scheduling
294 intrins Intrinsic method implementations
295 tailc Tail recursion and tail calls
296 loop Loop related optimizations
297 fcmov Fast x86 FP compares [arch-dependency]
298 leaf Leaf procedures optimizations
299 aot Usage of Ahead Of Time compiled code
300 precomp Precompile all methods before executing Main
301 abcrem Array bound checks removal
302 ssapre SSA based Partial Redundancy Elimination
303 sse2 SSE2 instructions on x86 [arch-dependency]
304 gshared Enable generic code sharing.
307 For example, to enable all the optimization but dead code
308 elimination and inlining, you can use:
310 -O=all,-deadce,-inline
313 The flags that are flagged with [arch-dependency] indicate that the
314 given option if used in combination with Ahead of Time compilation
315 (--aot flag) would produce pre-compiled code that will depend on the
316 current CPU and might not be safely moved to another computer.
318 \fB--runtime=VERSION\fR
319 Mono supports different runtime versions. The version used depends on the program
320 that is being run or on its configuration file (named program.exe.config). This option
321 can be used to override such autodetection, by forcing a different runtime version
322 to be used. Note that this should only be used to select a later compatible runtime
323 version than the one the program was compiled against. A typical usage is for
324 running a 1.1 program on a 2.0 version:
326 mono --runtime=v2.0.50727 program.exe
329 \fB--security\fR, \fB--security=mode\fR
330 Activate the security manager, a currently experimental feature in
331 Mono and it is OFF by default. The new code verifier can be enabled
332 with this option as well.
336 Using security without parameters is equivalent as calling it with the
339 The following modes are supported:
342 This allows mono to support declarative security attributes,
343 e.g. execution of Code Access Security (CAS) or non-CAS demands.
346 Enables the core-clr security system, typically used for
347 Moonlight/Silverlight applications. It provides a much simpler
348 security system than CAS, see http://www.mono-project.com/Moonlight
349 for more details and links to the descriptions of this new system.
352 Enables the new verifier and performs basic verification for code
353 validity. In this mode, unsafe code and P/Invoke are allowed. This
354 mode provides a better safety guarantee but it is still possible
355 for managed code to crash Mono.
358 Enables the new verifier and performs full verification of the code
359 being executed. It only allows verifiable code to be executed.
360 Unsafe code is not allowed but P/Invoke is. This mode should
361 not allow managed code to crash mono. The verification is not as
362 strict as ECMA 335 standard in order to stay compatible with the MS
365 The security system acts on user code: code contained in mscorlib or
366 the global assembly cache is always trusted.
371 Configures the virtual machine to be better suited for server
372 operations (currently, a no-op).
375 Verifies mscorlib and assemblies in the global
376 assembly cache for valid IL, and all user code for IL
379 This is different from \fB--security\fR's verifiable
380 or validil in that these options only check user code and skip
381 mscorlib and assemblies located on the global assembly cache.
383 \fB-V\fR, \fB--version\fR
384 Prints JIT version information (system configuration, release number
385 and branch names if available).
388 .SH DEVELOPMENT OPTIONS
389 The following options are used to help when developing a JITed application.
391 \fB--debug\fR, \fB--debug=OPTIONS\fR
392 Turns on the debugging mode in the runtime. If an assembly was
393 compiled with debugging information, it will produce line number
394 information for stack traces.
398 The optional OPTIONS argument is a comma separated list of debugging
399 options. These options are turned off by default since they generate
400 much larger and slower code at runtime.
402 The following options are supported:
405 Produces a detailed error when throwing a InvalidCastException. This
406 option needs to be enabled as this generates more verbose code at
410 Disable some JIT optimizations which are usually only disabled when
411 running inside the debugger. This can be helpful if you want to attach
412 to the running process with mdb.
415 Generate and register debugging information with gdb. This is only supported on some
416 platforms, and only when using gdb 7.0 or later.
420 \fB--profile[=profiler[:profiler_args]]\fR
421 Turns on profiling. For more information about profiling applications
422 and code coverage see the sections "PROFILING" and "CODE COVERAGE"
425 This option can be used multiple times, each time will load an
426 additional profiler. This allows developers to use modules that
427 extend the JIT through the Mono profiling interface.
429 \fB--trace[=expression]\fR
430 Shows method names as they are invoked. By default all methods are
433 The trace can be customized to include or exclude methods, classes or
434 assemblies. A trace expression is a comma separated list of targets,
435 each target can be prefixed with a minus sign to turn off a particular
436 target. The words `program', `all' and `disabled' have special
437 meaning. `program' refers to the main program being executed, and
438 `all' means all the method calls.
440 The `disabled' option is used to start up with tracing disabled. It
441 can be enabled at a later point in time in the program by sending the
442 SIGUSR2 signal to the runtime.
444 Assemblies are specified by their name, for example, to trace all
445 calls in the System assembly, use:
448 mono --trace=System app.exe
451 Classes are specified with the T: prefix. For example, to trace all
452 calls to the System.String class, use:
455 mono --trace=T:System.String app.exe
458 And individual methods are referenced with the M: prefix, and the
459 standard method notation:
462 mono --trace=M:System.Console:WriteLine app.exe
465 Exceptions can also be traced, it will cause a stack trace to be
466 printed every time an exception of the specified type is thrown.
467 The exception type can be specified with or without the namespace,
468 and to trace all exceptions, specify 'all' as the type name.
471 mono --trace=E:System.Exception app.exe
474 As previously noted, various rules can be specified at once:
477 mono --trace=T:System.String,T:System.Random app.exe
480 You can exclude pieces, the next example traces calls to
481 System.String except for the System.String:Concat method.
484 mono --trace=T:System.String,-M:System.String:Concat
487 Finally, namespaces can be specified using the N: prefix:
490 mono --trace=N:System.Xml
494 \fB--no-x86-stack-align\fR
495 Don't align stack frames on the x86 architecture. By default, Mono
496 aligns stack frames to 16 bytes on x86, so that local floating point
497 and SIMD variables can be properly aligned. This option turns off the
498 alignment, which usually saves one intruction per call, but might
499 result in significantly lower floating point and SIMD performance.
502 Generate a JIT method map in a /tmp/perf-PID.map file. This file is then
503 used, for example, by the perf tool included in recent Linux kernels.
504 Each line in the file has:
507 HEXADDR HEXSIZE methodname
510 Currently this option is only supported on Linux.
511 .SH JIT MAINTAINER OPTIONS
512 The maintainer options are only used by those developing the runtime
513 itself, and not typically of interest to runtime users or developers.
516 Inserts a breakpoint before the method whose name is `method'
517 (namespace.class:methodname). Use `Main' as method name to insert a
518 breakpoint on the application's main method.
521 Inserts a breakpoint on exceptions. This allows you to debug your
522 application with a native debugger when an exception is thrown.
525 This compiles a method (namespace.name:methodname), this is used for
526 testing the compiler performance or to examine the output of the code
530 Compiles all the methods in an assembly. This is used to test the
531 compiler performance or to examine the output of the code generator
533 \fB--graph=TYPE METHOD\fR
534 This generates a postscript file with a graph with the details about
535 the specified method (namespace.name:methodname). This requires `dot'
536 and ghostview to be installed (it expects Ghostview to be called
539 The following graphs are available:
541 cfg Control Flow Graph (CFG)
543 code CFG showing code
544 ssa CFG showing code after SSA translation
545 optcode CFG showing code after IR optimizations
548 Some graphs will only be available if certain optimizations are turned
552 Instruct the runtime on the number of times that the method specified
553 by --compile (or all the methods if --compileall is used) to be
554 compiled. This is used for testing the code generator performance.
557 Displays information about the work done by the runtime during the
558 execution of an application.
560 \fB--wapi=hps|semdel\fR
561 Perform maintenance of the process shared data.
563 semdel will delete the global semaphore.
565 hps will list the currently used handles.
567 \fB-v\fR, \fB--verbose\fR
568 Increases the verbosity level, each time it is listed, increases the
569 verbosity level to include more information (including, for example,
570 a disassembly of the native code produced, code selector info etc.).
572 The Mono runtime allows external processes to attach to a running
573 process and load assemblies into the running program. To attach to
574 the process, a special protocol is implemented in the Mono.Management
577 With this support it is possible to load assemblies that have an entry
578 point (they are created with -target:exe or -target:winexe) to be
579 loaded and executed in the Mono process.
581 The code is loaded into the root domain, and it starts execution on
582 the special runtime attach thread. The attached program should
583 create its own threads and return after invocation.
585 This support allows for example debugging applications by having the
586 csharp shell attach to running processes.
588 The mono runtime includes a profiler that can be used to explore
589 various performance related problems in your application. The
590 profiler is activated by passing the --profile command line argument
591 to the Mono runtime, the format is:
594 --profile[=profiler[:profiler_args]]
597 Mono has a built-in profiler called 'default' (and is also the default
598 if no arguments are specified), but developers can write custom
599 profilers, see the section "CUSTOM PROFILERS" for more details.
603 is not specified, the default profiler is used.
607 is a profiler-specific string of options for the profiler itself.
609 The default profiler accepts the following options 'alloc' to profile
610 memory consumption by the application; 'time' to profile the time
611 spent on each routine; 'jit' to collect time spent JIT-compiling methods
612 and 'stat' to perform sample statistical profiling.
613 If no options are provided the default is 'alloc,time,jit'.
616 profile data is printed to stdout: to change this, use the 'file=filename'
617 option to output the data to filename.
622 mono --profile program.exe
626 That will run the program with the default profiler and will do time
627 and allocation profiling.
631 mono --profile=default:stat,alloc,file=prof.out program.exe
634 Will do sample statistical profiling and allocation profiling on
635 program.exe. The profile data is put in prof.out.
637 Note that the statistical profiler has a very low overhead and should
638 be the preferred profiler to use (for better output use the full path
639 to the mono binary when running and make sure you have installed the
640 addr2line utility that comes from the binutils package).
642 This is the most advanced profiler.
644 The Mono \f[I]log\f[] profiler can be used to collect a lot of
645 information about a program running in the Mono runtime.
646 This data can be used (both while the process is running and later)
647 to do analyses of the program behaviour, determine resource usage,
648 performance issues or even look for particular execution patterns.
650 This is accomplished by logging the events provided by the Mono
651 runtime through the profiling interface and periodically writing
652 them to a file which can be later inspected with the mprof-report(1)
655 More information about how to use the log profiler is available on the
656 mprof-report(1) page.
658 Mono provides a mechanism for loading other profiling modules which in
659 the form of shared libraries. These profiling modules can hook up to
660 various parts of the Mono runtime to gather information about the code
663 To use a third party profiler you must pass the name of the profiler
667 mono --profile=custom program.exe
671 In the above sample Mono will load the user defined profiler from the
672 shared library `mono-profiler-custom.so'. This profiler module must
673 be on your dynamic linker library path.
675 A list of other third party profilers is available from Mono's web
676 site (www.mono-project.com/Performance_Tips)
678 Custom profiles are written as shared libraries. The shared library
679 must be called `mono-profiler-NAME.so' where `NAME' is the name of
682 For a sample of how to write your own custom profiler look in the
683 Mono source tree for in the samples/profiler.c.
685 Mono ships with a code coverage module. This module is activated by
686 using the Mono --profile=cov option. The format is:
687 \fB--profile=cov[:assembly-name[/namespace]] test-suite.exe\fR
689 By default code coverage will default to all the assemblies loaded,
690 you can limit this by specifying the assembly name, for example to
691 perform code coverage in the routines of your program use, for example
692 the following command line limits the code coverage to routines in the
696 mono --profile=cov:demo demo.exe
702 does not include the extension.
704 You can further restrict the code coverage output by specifying a
708 mono --profile=cov:demo/My.Utilities demo.exe
712 Which will only perform code coverage in the given assembly and
715 Typical output looks like this:
718 Not covered: Class:.ctor ()
719 Not covered: Class:A ()
720 Not covered: Driver:.ctor ()
721 Not covered: Driver:method ()
722 Partial coverage: Driver:Main ()
727 The offsets displayed are IL offsets.
729 A more powerful coverage tool is available in the module `monocov'.
730 See the monocov(1) man page for details.
732 To debug managed applications, you can use the
734 command, a command line debugger.
736 It is possible to obtain a stack trace of all the active threads in
737 Mono by sending the QUIT signal to Mono, you can do this from the
738 command line, like this:
744 Where pid is the Process ID of the Mono process you want to examine.
745 The process will continue running afterwards, but its state is not
749 this is a last-resort mechanism for debugging applications and should
750 not be used to monitor or probe a production application. The
751 integrity of the runtime after sending this signal is not guaranteed
752 and the application might crash or terminate at any given point
755 The \fB--debug=casts\fR option can be used to get more detailed
756 information for Invalid Cast operations, it will provide information
757 about the types involved.
759 You can use the MONO_LOG_LEVEL and MONO_LOG_MASK environment variables
760 to get verbose debugging output about the execution of your
761 application within Mono.
765 environment variable if set, the logging level is changed to the set
766 value. Possible values are "error", "critical", "warning", "message",
767 "info", "debug". The default value is "error". Messages with a logging
768 level greater then or equal to the log level will be printed to
771 Use "info" to track the dynamic loading of assemblies.
776 environment variable to limit the extent of the messages you get:
777 If set, the log mask is changed to the set value. Possible values are
778 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
779 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
780 "security" (e.g. Moonlight CoreCLR support) and "all".
781 The default value is "all". Changing the mask value allows you to display only
782 messages for a certain component. You can use multiple masks by comma
783 separating them. For example to see config file messages and assembly loader
784 messages set you mask to "asm,cfg".
786 The following is a common use to track down problems with P/Invoke:
789 $ MONO_LOG_LEVEL="debug" MONO_LOG_MASK="dll" mono glue.exe
794 Mono's XML serialization engine by default will use a reflection-based
795 approach to serialize which might be slow for continuous processing
796 (web service applications). The serialization engine will determine
797 when a class must use a hand-tuned serializer based on a few
798 parameters and if needed it will produce a customized C# serializer
799 for your types at runtime. This customized serializer then gets
800 dynamically loaded into your application.
802 You can control this with the MONO_XMLSERIALIZER_THS environment
805 The possible values are
807 to disable the use of a C# customized
808 serializer, or an integer that is the minimum number of uses before
809 the runtime will produce a custom serializer (0 will produce a
810 custom serializer on the first access, 50 will produce a serializer on
811 the 50th use). Mono will fallback to an interpreted serializer if the
812 serializer generation somehow fails. This behavior can be disabled
813 by setting the option
815 (for example: MONO_XMLSERIALIZER_THS=0,nofallback).
816 .SH ENVIRONMENT VARIABLES
819 Turns off the garbage collection in Mono. This should be only used
820 for debugging purposes
823 When Mono is compiled with LLVM support, this instructs the runtime to
824 stop using LLVM after the specified number of methods are JITed.
825 This is a tool used in diagnostics to help isolate problems in the
826 code generation backend. For example \fBLLVM_COUNT=10\fR would only
827 compile 10 methods with LLVM and then switch to the Mono JIT engine.
828 \fBLLVM_COUNT=0\fR would disable the LLVM engine altogether.
831 If set, this variable will instruct Mono to ahead-of-time compile new
832 assemblies on demand and store the result into a cache in
835 \fBMONO_ASPNET_INHIBIT_SETTINGSMAP\fR
836 Mono contains a feature which allows modifying settings in the .config files shipped
837 with Mono by using config section mappers. The mappers and the mapping rules are
838 defined in the $prefix/etc/mono/2.0/settings.map file and, optionally, in the
839 settings.map file found in the top-level directory of your ASP.NET application.
840 Both files are read by System.Web on application startup, if they are found at the
841 above locations. If you don't want the mapping to be performed you can set this
842 variable in your environment before starting the application and no action will
846 If set, this variable overrides the default system configuration directory
847 ($PREFIX/etc). It's used to locate machine.config file.
850 Sets the style of COM interop. If the value of this variable is "MS"
851 Mono will use string marhsalling routines from the liboleaut32 for the
852 BSTR type library, any other values will use the mono-builtin BSTR
856 If set, this variable overrides the default runtime configuration file
857 ($PREFIX/etc/mono/config). The --config command line options overrides the
858 environment variable.
861 Override the automatic cpu detection mechanism. Currently used only on arm.
862 The format of the value is as follows:
868 where V is the architecture number 4, 5, 6, 7 and the options can be currently be
872 MONO_CPU_ARCH="armv4 thumb" mono ...
876 \fBMONO_DISABLE_AIO\fR
877 If set, tells mono NOT to attempt using native asynchronous I/O services. In
878 that case, a default select/poll implementation is used. Currently only epoll()
881 \fBMONO_DISABLE_MANAGED_COLLATION\fR
882 If this environment variable is `yes', the runtime uses unmanaged
883 collation (which actually means no culture-sensitive collation). It
884 internally disables managed collation functionality invoked via the
885 members of System.Globalization.CompareInfo class. Collation is
888 \fBMONO_DISABLE_SHM\fR
889 Unix only: If set, disables the shared memory files used for
890 cross-process handles: process have only private handles. This means
891 that process and thread handles are not available to other processes,
892 and named mutexes, named events and named semaphores are not visible
895 This is can also be enabled by default by passing the
896 "--disable-shared-handles" option to configure.
898 This is the default from mono 2.8 onwards.
900 \fBMONO_EGD_SOCKET\fR
901 For platforms that do not otherwise have a way of obtaining random bytes
902 this can be set to the name of a file system socket on which an egd or
903 prngd daemon is listening.
905 \fBMONO_ENABLE_SHM\fR
906 Unix only: Enable support for cross-process handles. Cross-process
907 handles are used to expose process handles, thread handles, named
908 mutexes, named events and named semaphores across Unix processes.
910 \fBMONO_ENV_OPTIONS\fR
911 This environment variable allows you to pass command line arguments to
912 a Mono process through the environment. This is useful for example
913 to force all of your Mono processes to use LLVM or SGEN without having
914 to modify any launch scripts.
916 \fBMONO_EVENTLOG_TYPE\fR
917 Sets the type of event log provider to use (for System.Diagnostics.EventLog).
924 Persists event logs and entries to the local file system.
926 The directory in which to persist the event logs, event sources and entries
927 can be specified as part of the value.
929 If the path is not explicitly set, it defaults to "/var/lib/mono/eventlog"
930 on unix and "%APPDATA%\mono\eventlog" on Windows.
935 Uses the native win32 API to write events and registers event logs and
936 event sources in the registry. This is only available on Windows.
938 On Unix, the directory permission for individual event log and event source
939 directories is set to 777 (with +t bit) allowing everyone to read and write
940 event log entries while only allowing entries to be deleted by the user(s)
945 Silently discards any events.
948 The default is "null" on Unix (and versions of Windows before NT), and
949 "win32" on Windows NT (and higher).
952 \fBMONO_EXTERNAL_ENCODINGS\fR
953 If set, contains a colon-separated list of text encodings to try when
954 turning externally-generated text (e.g. command-line arguments or
955 filenames) into Unicode. The encoding names come from the list
956 provided by iconv, and the special case "default_locale" which refers
957 to the current locale's default encoding.
959 When reading externally-generated text strings UTF-8 is tried first,
960 and then this list is tried in order with the first successful
961 conversion ending the search. When writing external text (e.g. new
962 filenames or arguments to new processes) the first item in this list
963 is used, or UTF-8 if the environment variable is not set.
965 The problem with using MONO_EXTERNAL_ENCODINGS to process your
966 files is that it results in a problem: although its possible to get
967 the right file name it is not necessarily possible to open the file.
968 In general if you have problems with encodings in your filenames you
969 should use the "convmv" program.
972 When using Mono with the SGen garbage collector this variable controls
973 several parameters of the collector. The variable's value is a comma
974 separated list of words.
978 \fBnursery-size=\fIsize\fR
979 Sets the size of the nursery. The size is specified in bytes and must
980 be a power of two. The suffixes `k', `m' and `g' can be used to
981 specify kilo-, mega- and gigabytes, respectively. The nursery is the
982 first generation (of two). A larger nursery will usually speed up the
983 program but will obviously use more memory. The default nursery size
986 \fBmajor=\fIcollector\fR
987 Specifies which major collector to use. Options are `marksweep' for
988 the Mark&Sweep collector, `marksweep-par' for parallel Mark&Sweep,
989 `marksweep-fixed' for Mark&Sweep with a fixed heap,
990 `marksweep-fixed-par' for parallel Mark&Sweep with a fixed heap and
991 `copying' for the copying collector. The Mark&Sweep collector is the
994 \fBmajor-heap-size=\fIsize\fR
995 Sets the size of the major heap (not including the large object space)
996 for the fixed-heap Mark&Sweep collector (i.e. `marksweep-fixed' and
997 `marksweep-fixed-par'). The size is in bytes, with optional suffixes
998 `k', `m' and `g' to specify kilo-, mega- and gigabytes, respectively.
999 The default is 512 megabytes.
1001 \fBwbarrier=\fIwbarrier\fR
1002 Specifies which write barrier to use. Options are `cardtable' and
1003 `remset'. The card table barrier is faster but less precise, and only
1004 supported for the Mark&Sweep major collector on 32 bit platforms. The
1005 default is `cardtable' if it is supported, otherwise `remset'. The cardtable
1006 write barrier is faster and has a more stable and usually smaller
1007 memory footprint. If the program causes too much pinning during
1008 thread scan, it might be faster to enable remset.
1010 \fBevacuation-threshold=\fIthreshold\fR
1011 Sets the evacuation threshold in percent. This option is only available
1012 on the Mark&Sweep major collectors. The value must be an
1013 integer in the range 0 to 100. The default is 66. If the sweep phase of
1014 the collection finds that the occupancy of a specific heap block type is
1015 less than this percentage, it will do a copying collection for that block
1016 type in the next major collection, thereby restoring occupancy to close
1017 to 100 percent. A value of 0 turns evacuation off.
1019 \fB(no-)concurrent-sweep\fR
1020 Enables or disables concurrent sweep for the Mark&Sweep collector. If
1021 enabled, the sweep phase of the garbage collection is done in a thread
1022 concurrently with the application. Concurrent sweep is disabled by
1028 When using Mono with the SGen garbage collector this environment
1029 variable can be used to turn on various debugging features of the
1030 collector. The value of this variable is a comma separated list of
1036 Sets the debug level to the specified number.
1038 \fBcollect-before-allocs\fR
1040 \fBcheck-at-minor-collections\fR
1041 This performs a consistency check on minor collections and also clears
1042 the nursery at collection time, instead of the default, when buffers
1043 are allocated (clear-at-gc). The consistency check ensures that
1044 there are no major to minor references that are not on the remembered
1047 \fBxdomain-checks\fR
1048 Performs a check to make sure that no references are left to an
1052 This clears the nursery at GC time instead of doing it when the thread
1053 local allocation buffer (TLAB) is created. The default is to clear
1054 the nursery at TLAB creation time.
1056 \fBconservative-stack-mark\fR
1057 Forces the GC to scan the stack conservatively, even if precise
1058 scanning is available.
1060 \fBcheck-scan-starts\fR
1061 If set, does a plausibility check on the scan_starts before and after each collection
1063 \fBheap-dump=\fIfile\fR
1064 Dumps the heap contents to the specified file. To visualize the
1065 information, use the mono-heapviz tool.
1067 \fBbinary-protocol=\fIfile\fR
1068 Outputs the debugging output to the specified file. For this to
1069 work, Mono needs to be compiled with the BINARY_PROTOCOL define on
1070 sgen-gc.c. You can then use this command to explore the output
1072 sgen-grep-binprot 0x1234 0x5678 < file
1077 \fBMONO_GAC_PREFIX\fR
1078 Provides a prefix the runtime uses to look for Global Assembly Caches.
1079 Directories are separated by the platform path separator (colons on
1080 unix). MONO_GAC_PREFIX should point to the top directory of a prefixed
1081 install. Or to the directory provided in the gacutil /gacdir command. Example:
1082 .B /home/username/.mono:/usr/local/mono/
1085 Enables some filename rewriting support to assist badly-written
1086 applications that hard-code Windows paths. Set to a colon-separated
1087 list of "drive" to strip drive letters, or "case" to do
1088 case-insensitive file matching in every directory in a path. "all"
1089 enables all rewriting methods. (Backslashes are always mapped to
1090 slashes if this variable is set to a valid option).
1093 For example, this would work from the shell:
1096 MONO_IOMAP=drive:case
1100 If you are using mod_mono to host your web applications, you can use
1103 directive instead, like this:
1106 MonoIOMAP <appalias> all
1109 See mod_mono(8) for more details.
1111 Additionally. Mono includes a profiler module which allows one to track what
1112 adjustements to file paths IOMAP code needs to do. The tracking code reports
1113 the managed location (full stack trace) from which the IOMAP-ed call was made and,
1114 on process exit, the locations where all the IOMAP-ed strings were created in
1115 managed code. The latter report is only approximate as it is not always possible
1116 to estimate the actual location where the string was created. The code uses simple
1117 heuristics - it analyzes stack trace leading back to the string allocation location
1118 and ignores all the managed code which lives in assemblies installed in GAC as well as in the
1119 class libraries shipped with Mono (since they are assumed to be free of case-sensitivity
1120 issues). It then reports the first location in the user's code - in most cases this will be
1121 the place where the string is allocated or very close to the location. The reporting code
1122 is implemented as a custom profiler module (see the "PROFILING" section) and can be loaded
1123 in the following way:
1128 mono --profile=iomap yourapplication.exe
1131 Note, however, that Mono currently supports only one profiler module
1135 When Mono is using the LLVM code generation backend you can use this
1136 environment variable to pass code generation options to the LLVM
1139 \fBMONO_MANAGED_WATCHER\fR
1140 If set to "disabled", System.IO.FileSystemWatcher will use a file watcher
1141 implementation which silently ignores all the watching requests.
1142 If set to any other value, System.IO.FileSystemWatcher will use the default
1143 managed implementation (slow). If unset, mono will try to use inotify, FAM,
1144 Gamin, kevent under Unix systems and native API calls on Windows, falling
1145 back to the managed implementation on error.
1147 \fBMONO_MESSAGING_PROVIDER\fR
1148 Mono supports a plugin model for its implementation of System.Messaging making
1149 it possible to support a variety of messaging implementations (e.g. AMQP, ActiveMQ).
1150 To specify which messaging implementation is to be used the evironement variable
1151 needs to be set to the full class name for the provider. E.g. to use the RabbitMQ based
1152 AMQP implementation the variable should be set to:
1155 Mono.Messaging.RabbitMQ.RabbitMQMessagingProvider,Mono.Messaging.RabbitMQ
1158 If set causes the mono process to be bound to a single processor. This may be
1159 useful when debugging or working around race conditions.
1162 Disable inlining of thread local accesses. Try setting this if you get a segfault
1163 early on in the execution of mono.
1166 Provides a search path to the runtime where to look for library
1167 files. This is a tool convenient for debugging applications, but
1168 should not be used by deployed applications as it breaks the assembly
1169 loader in subtle ways.
1171 Directories are separated by the platform path separator (colons on unix). Example:
1172 .B /home/username/lib:/usr/local/mono/lib
1174 Alternative solutions to MONO_PATH include: installing libraries into
1175 the Global Assembly Cache (see gacutil(1)) or having the dependent
1176 libraries side-by-side with the main executable.
1178 For a complete description of recommended practices for application
1180 http://www.mono-project.com/Guidelines:Application_Deployment
1183 Experimental RTC support in the statistical profiler: if the user has
1184 the permission, more accurate statistics are gathered. The MONO_RTC
1185 value must be restricted to what the Linux rtc allows: power of two
1186 from 64 to 8192 Hz. To enable higher frequencies like 4096 Hz, run as root:
1189 echo 4096 > /proc/sys/dev/rtc/max-user-freq
1196 MONO_RTC=4096 mono --profiler=default:stat program.exe
1200 \fBMONO_SHARED_DIR\fR
1201 If set its the directory where the ".wapi" handle state is stored.
1202 This is the directory where the Windows I/O Emulation layer stores its
1203 shared state data (files, events, mutexes, pipes). By default Mono
1204 will store the ".wapi" directory in the users's home directory.
1206 \fBMONO_SHARED_HOSTNAME\fR
1207 Uses the string value of this variable as a replacement for the host name when
1208 creating file names in the ".wapi" directory. This helps if the host name of
1209 your machine is likely to be changed when a mono application is running or if
1210 you have a .wapi directory shared among several different computers.
1212 Mono typically uses the hostname to create the files that are used to
1213 share state across multiple Mono processes. This is done to support
1214 home directories that might be shared over the network.
1216 \fBMONO_STRICT_IO_EMULATION\fR
1217 If set, extra checks are made during IO operations. Currently, this
1218 includes only advisory locks around file writes.
1221 The name of the theme to be used by Windows.Forms. Available themes today
1222 include "clearlooks", "nice" and "win32".
1224 The default is "win32".
1226 \fBMONO_TLS_SESSION_CACHE_TIMEOUT\fR
1227 The time, in seconds, that the SSL/TLS session cache will keep it's entry to
1228 avoid a new negotiation between the client and a server. Negotiation are very
1229 CPU intensive so an application-specific custom value may prove useful for
1230 small embedded systems.
1232 The default is 180 seconds.
1234 \fBMONO_THREADS_PER_CPU\fR
1235 The maximum number of threads in the general threadpool will be
1236 20 + (MONO_THREADS_PER_CPU * number of CPUs). The default value for this
1239 \fBMONO_XMLSERIALIZER_THS\fR
1240 Controls the threshold for the XmlSerializer to produce a custom
1241 serializer for a given class instead of using the Reflection-based
1242 interpreter. The possible values are `no' to disable the use of a
1243 custom serializer or a number to indicate when the XmlSerializer
1244 should start serializing. The default value is 50, which means that
1245 the a custom serializer will be produced on the 50th use.
1247 \fBMONO_X509_REVOCATION_MODE\fR
1248 Sets the revocation mode used when validating a X509 certificate chain (https,
1249 ftps, smtps...). The default is 'nocheck', which performs no revocation check
1250 at all. The other possible values are 'offline', which performs CRL check (not
1251 implemented yet) and 'online' which uses OCSP and CRL to verify the revocation
1252 status (not implemented yet).
1253 .SH ENVIRONMENT VARIABLES FOR DEBUGGING
1255 \fBMONO_ASPNET_NODELETE\fR
1256 If set to any value, temporary source files generated by ASP.NET support
1257 classes will not be removed. They will be kept in the user's temporary
1261 If set, enables some features of the runtime useful for debugging.
1262 This variable should contain a comma separated list of debugging options.
1263 Currently, the following options are supported:
1267 \fBbreak-on-unverified\fR
1268 If this variable is set, when the Mono VM runs into a verification
1269 problem, instead of throwing an exception it will break into the
1270 debugger. This is useful when debugging verifier problems
1273 This option can be used to get more detailed information from
1274 InvalidCast exceptions, it will provide information about the types
1277 \fBcollect-pagefault-stats\fR
1278 Collects information about pagefaults. This is used internally to
1279 track the number of page faults produced to load metadata. To display
1280 this information you must use this option with "--stats" command line
1283 \fBdont-free-domains\fR
1284 This is an Optimization for multi-AppDomain applications (most
1285 commonly ASP.NET applications). Due to internal limitations Mono,
1286 Mono by default does not use typed allocations on multi-appDomain
1287 applications as they could leak memory when a domain is unloaded.
1289 Although this is a fine default, for applications that use more than
1290 on AppDomain heavily (for example, ASP.NET applications) it is worth
1291 trading off the small leaks for the increased performance
1292 (additionally, since ASP.NET applications are not likely going to
1293 unload the application domains on production systems, it is worth
1294 using this feature).
1296 \fBdyn-runtime-invoke\fR
1297 Instructs the runtime to try to use a generic runtime-invoke wrapper
1298 instead of creating one invoke wrapper.
1301 Equivalent to setting the \fBMONO_XDEBUG\fR variable, this emits
1302 symbols into a shared library as the code is JITed that can be loaded
1303 into GDB to inspect symbols.
1305 \fBgen-seq-points\fR
1306 Automatically generates sequence points where the
1307 IL stack is empty. These are places where the debugger can set a
1310 \fBexplicit-null-checks\fR
1311 Makes the JIT generate an explicit NULL check on variable dereferences
1312 instead of depending on the operating system to raise a SIGSEGV or
1313 another form of trap event when an invalid memory location is
1317 Captures the interrupt signal (Control-C) and displays a stack trace
1318 when pressed. Useful to find out where the program is executing at a
1319 given point. This only displays the stack trace of a single thread.
1322 Instructs the runtime to initialize the stack with
1323 some known values (0x2a on x86-64) at the start of a method to assist
1324 in debuggin the JIT engine.
1326 \fBkeep-delegates\fR
1327 This option will leak delegate trampolines that are no longer
1328 referenced as to present the user with more information about a
1329 delegate misuse. Basically a delegate instance might be created,
1330 passed to unmanaged code, and no references kept in managed code,
1331 which will garbage collect the code. With this option it is possible
1332 to track down the source of the problems.
1334 \fBreverse-pinvoke-exceptions
1335 This option will cause mono to abort with a descriptive message when
1336 during stack unwinding after an exception it reaches a native stack
1337 frame. This happens when a managed delegate is passed to native code,
1338 and the managed delegate throws an exception. Mono will normally try
1339 to unwind the stack to the first (managed) exception handler, and it
1340 will skip any native stack frames in the process. This leads to
1341 undefined behaviour (since mono doesn't know how to process native
1342 frames), leaks, and possibly crashes too.
1344 \fBno-gdb-backtrace\fR
1345 This option will disable the GDB backtrace emitted by the runtime
1346 after a SIGSEGV or SIGABRT in unmanaged code.
1348 \fBsuspend-on-sigsegv\fR
1349 This option will suspend the program when a native SIGSEGV is received.
1350 This is useful for debugging crashes which do not happen under gdb,
1351 since a live process contains more information than a core file.
1355 \fBMONO_LOG_LEVEL\fR
1356 The logging level, possible values are `error', `critical', `warning',
1357 `message', `info' and `debug'. See the DEBUGGING section for more
1361 Controls the domain of the Mono runtime that logging will apply to.
1362 If set, the log mask is changed to the set value. Possible values are
1363 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1364 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1365 "security" (e.g. Moonlight CoreCLR support) and "all".
1366 The default value is "all". Changing the mask value allows you to display only
1367 messages for a certain component. You can use multiple masks by comma
1368 separating them. For example to see config file messages and assembly loader
1369 messages set you mask to "asm,cfg".
1372 Used for runtime tracing of method calls. The format of the comma separated
1381 disabled Trace output off upon start.
1384 You can toggle trace output on/off sending a SIGUSR2 signal to the program.
1386 \fBMONO_TRACE_LISTENER\fR
1387 If set, enables the System.Diagnostics.DefaultTraceListener, which will
1388 print the output of the System.Diagnostics Trace and Debug classes.
1389 It can be set to a filename, and to Console.Out or Console.Error to display
1390 output to standard output or standard error, respectively. If it's set to
1391 Console.Out or Console.Error you can append an optional prefix that will
1392 be used when writing messages like this: Console.Error:MyProgramName.
1393 See the System.Diagnostics.DefaultTraceListener documentation for more
1396 \fBMONO_XEXCEPTIONS\fR
1397 This throws an exception when a X11 error is encountered; by default a
1398 message is displayed but execution continues
1400 \fBMONO_XMLSERIALIZER_DEBUG\fR
1401 Set this value to 1 to prevent the serializer from removing the
1402 temporary files that are created for fast serialization; This might
1403 be useful when debugging.
1406 This is used in the System.Windows.Forms implementation when running
1407 with the X11 backend. This is used to debug problems in Windows.Forms
1408 as it forces all of the commands send to X11 server to be done
1409 synchronously. The default mode of operation is asynchronous which
1410 makes it hard to isolate the root of certain problems.
1412 \fBMONO_GENERIC_SHARING\fR
1413 This environment variable controls the kind of generic sharing used.
1414 This variable is used by internal JIT developers and should not be
1415 changed in production. Do not use it.
1417 The variable controls which classes will have generic code sharing
1420 Permissible values are:
1424 All generated code can be shared.
1427 Only the classes in System.Collections.Generic will have its code
1428 shared (this is the default value).
1431 Only code in corlib will have its code shared.
1434 No generic code sharing will be performed.
1437 Generic code sharing by default only applies to collections. The
1438 Mono JIT by default turns this on.
1441 When the the MONO_XDEBUG env var is set, debugging info for JITted
1442 code is emitted into a shared library, loadable into gdb. This enables,
1443 for example, to see managed frame names on gdb backtraces.
1445 \fBMONO_VERBOSE_METHOD\fR
1446 Enables the maximum JIT verbosity for the specified method. This is
1447 very helpfull to diagnose a miscompilation problems of a specific
1450 If you want to use Valgrind, you will find the file `mono.supp'
1451 useful, it contains the suppressions for the GC which trigger
1452 incorrect warnings. Use it like this:
1454 valgrind --suppressions=mono.supp mono ...
1457 On some platforms, Mono can expose a set of DTrace probes (also known
1458 as user-land statically defined, USDT Probes).
1460 They are defined in the file `mono.d'.
1462 .B ves-init-begin, ves-init-end
1464 Begin and end of runtime initialization.
1466 .B method-compile-begin, method-compile-end
1468 Begin and end of method compilation.
1469 The probe arguments are class name, method name and signature,
1470 and in case of method-compile-end success or failure of compilation.
1474 Begin and end of Garbage Collection.
1476 To verify the availability of the probes, run:
1478 dtrace -P mono'$target' -l -c mono
1481 Mono's Ping implementation for detecting network reachability can
1482 create the ICMP packets itself without requiring the system ping
1483 command to do the work. If you want to enable this on Linux for
1484 non-root users, you need to give the Mono binary special permissions.
1486 As root, run this command:
1488 # setcap cap_net_raw=+ep /usr/bin/mono
1491 On Unix assemblies are loaded from the installation lib directory. If you set
1492 `prefix' to /usr, the assemblies will be located in /usr/lib. On
1493 Windows, the assemblies are loaded from the directory where mono and
1496 .B ~/.mono/aot-cache
1498 The directory for the ahead-of-time compiler demand creation
1499 assemblies are located.
1501 .B /etc/mono/config, ~/.mono/config
1503 Mono runtime configuration file. See the mono-config(5) manual page
1504 for more information.
1506 .B ~/.config/.mono/certs, /usr/share/.mono/certs
1508 Contains Mono certificate stores for users / machine. See the certmgr(1)
1509 manual page for more information on managing certificate stores and
1510 the mozroots(1) page for information on how to import the Mozilla root
1511 certificates into the Mono certificate store.
1513 .B ~/.mono/assemblies/ASSEMBLY/ASSEMBLY.config
1515 Files in this directory allow a user to customize the configuration
1516 for a given system assembly, the format is the one described in the
1517 mono-config(5) page.
1519 .B ~/.config/.mono/keypairs, /usr/share/.mono/keypairs
1521 Contains Mono cryptographic keypairs for users / machine. They can be
1522 accessed by using a CspParameters object with DSACryptoServiceProvider
1523 and RSACryptoServiceProvider classes.
1525 .B ~/.config/.isolatedstorage, ~/.local/share/.isolatedstorage, /usr/share/.isolatedstorage
1527 Contains Mono isolated storage for non-roaming users, roaming users and
1528 local machine. Isolated storage can be accessed using the classes from
1529 the System.IO.IsolatedStorage namespace.
1531 .B <assembly>.config
1533 Configuration information for individual assemblies is loaded by the
1534 runtime from side-by-side files with the .config files, see the
1535 http://www.mono-project.com/Config for more information.
1537 .B Web.config, web.config
1539 ASP.NET applications are configured through these files, the
1540 configuration is done on a per-directory basis. For more information
1541 on this subject see the http://www.mono-project.com/Config_system.web
1544 Mailing lists are listed at the
1545 http://www.mono-project.com/Mailing_Lists
1547 http://www.mono-project.com
1550 certmgr(1), csharp(1), mcs(1), mdb(1), monocov(1), monodis(1),
1551 mono-config(5), mozroots(1), pdb2mdb(1), xsp(1), mod_mono(8).
1553 For more information on AOT:
1554 http://www.mono-project.com/AOT
1556 For ASP.NET-related documentation, see the xsp(1) manual page
projects / mono.git / blob