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 contains a native code generator that transforms the
23 Common Intermediate Language into native code.
25 The code generator can operate in two modes: just in time compilation
26 (JIT) or ahead of time compilation (AOT). Since code can be
27 dynamically loaded, the runtime environment and the JIT are always
28 present, even if code is compiled ahead of time.
30 The runtime loads the specified
37 is an ECMA assembly. They typically have a .exe or .dll extension.
39 The runtime provides a number of configuration options for running
40 applications, for developing and debugging, and for testing and
41 debugging the runtime itself.
43 The \fImono\fP command uses the Boehm conservative garbage collector
44 while the \fImono-sgen\fP command uses a moving and generational
47 On Unix-based systems, Mono provides a mechanism to emulate the
48 Windows-style file access, this includes providing a case insensitive
49 view of the file system, directory separator mapping (from \\ to /) and
50 stripping the drive letters.
52 This functionality is enabled by setting the
54 environment variable to one of
59 See the description for
61 in the environment variables section for more details.
63 The following options are available:
65 \fB--aot\fR, \fB--aot[=options]\fR
66 This option is used to precompile the CIL code in the specified
67 assembly to native code. The generated code is stored in a file with
68 the extension .so. This file will be automatically picked up by the
69 runtime when the assembly is executed.
71 Ahead-of-Time compilation is most useful if you use it in combination
72 with the -O=all,-shared flag which enables all of the optimizations in
73 the code generator to be performed. Some of those optimizations are
74 not practical for Just-in-Time compilation since they might be very
77 Unlike the .NET Framework, Ahead-of-Time compilation will not generate
78 domain independent code: it generates the same code that the
79 Just-in-Time compiler would produce. Since most applications use a
80 single domain, this is fine. If you want to optimize the generated
81 code for use in multi-domain applications, consider using the
84 This pre-compiles the methods, but the original assembly is still
85 required to execute as this one contains the metadata and exception
86 information which is not available on the generated file. When
87 precompiling code, you might want to compile with all optimizations
88 (-O=all). Pre-compiled code is position independent code.
90 Pre compilation is just a mechanism to reduce startup time, increase
91 code sharing across multiple mono processes and avoid just-in-time
92 compilation program startup costs. The original assembly must still
93 be present, as the metadata is contained there.
95 AOT code typically can not be moved from one computer to another
96 (CPU-specific optimizations that are detected at runtime) so you
97 should not try to move the pre-generated assemblies or package the
98 pre-generated assemblies for deployment.
100 A few options are available as a parameter to the
102 command line option. The options are separated by commas, and more
103 than one can be specified:
108 The AOT compiler will emit a (ELF only) library initializer to automatically
109 register the aot compiled module with the runtime. This is only useful in static
113 Instructs the AOT compiler to output assembly code instead of an
116 .I bind-to-runtime-version
118 If specified, forces the generated AOT files to be bound to the
119 runtime version of the compiling Mono. This will prevent the AOT
120 files from being consumed by a different Mono runtime.
123 This is currently an experimental feature as it is not complete.
124 This instructs Mono to precompile code that has historically not been
125 precompiled with AOT.
129 When this option is specified, P/Invoke methods are invoked directly
130 instead of going through the operating system symbol lookup operation.
132 .I llvm-path=<PREFIX>
133 Same for the llvm tools 'opt' and 'llc'.
136 Use the GNU style target triple <TRIPLE> to determine some code generation options, i.e.
137 --mtriple=armv7-linux-gnueabi will generate code that targets ARMv7. This is currently
138 only supported by the ARM backend. In LLVM mode, this triple is passed on to the LLVM
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.
147 Instructs the AOT compiler to not output any debugging information.
150 This prevents the AOT compiler from generating a direct calls to a
151 method. The AOT compiler usually generates direct calls for certain
152 methods that do not require going through the PLT (for example,
153 methods that are known to not require a hook like a static
154 constructor) or call into simple internal calls.
157 Instructs the AOT compiler to emit DWARF debugging information. When
158 used together with the nodebug option, only DWARF debugging
159 information is emitted, but not the information that can be used at
162 .I nrgctx-trampolines=[number]
163 When compiling in full aot mode, the generic sharing trampolines must be precreated
164 in the AOT image. You can add additional method trampolines with this argument.
167 .I ntrampolines=[number]
168 When compiling in full aot mode, the method trampolines must be precreated
169 in the AOT image. You can add additional method trampolines with this argument.
172 .I outfile=[filename]
173 Instructs the AOT compiler to save the output to the specified file.
175 .I print-skipped-methods
176 If the AOT compiler cannot compile a method for any reason, enabling this flag
177 will output the skipped methods to the console.
179 .I readonly-value=namespace.typename.fieldname=type/value
180 Override the value of a static readonly field. Usually, during JIT
181 compilation, the static constructor is ran eagerly, so the value of
182 a static readonly field is known at compilation time and the compiler
183 can do a number of optimizations based on it. During AOT, instead, the static
184 constructor can't be ran, so this option can be used to set the value of such
185 a field and enable the same set of optimizations.
186 Type can be any of i1, i2, i4 for integers of the respective sizes (in bytes).
187 Note that signed/unsigned numbers do not matter here, just the storage size.
188 This option can be specified multiple times and it doesn't prevent the static
189 constructor for the type defining the field to execute with the usual rules
190 at runtime (hence possibly computing a different value for the field).
193 .I save-temps,keep-temps
194 Instructs the AOT compiler to keep temporary files.
197 This instructs the compiler to generate sequence point checks that
198 allow Mono's soft debugger to debug applications even on systems where
199 it is not possible to set breakpoints or to single step (certain
200 hardware configurations like the cell phones and video gaming
204 Create an ELF object file (.o) or .s file which can be statically linked into an
205 executable when embedding the mono runtime. When this option is used, the object file
206 needs to be registered with the embedded runtime using the mono_aot_register_module
207 function which takes as its argument the mono_aot_module_<ASSEMBLY NAME>_info global
208 symbol from the object file:
211 extern void *mono_aot_module_hello_info;
213 mono_aot_register_module (mono_aot_module_hello_info);
218 Print various stats collected during AOT compilation.
221 This is an experimental option for the AOT compiler to use multiple threads
222 when compiling the methods.
224 .I tool-prefix=<PREFIX>
225 Prepends <PREFIX> to the name of tools ran by the AOT compiler, i.e. 'as'/'ld'. For
226 example, --tool=prefix=arm-linux-gnueabi- will make the AOT compiler run
227 'arm-linux-gnueabi-as' instead of 'as'.
230 Instructs the AOT compiler to emit debug symbol information.
232 For more information about AOT, see: http://www.mono-project.com/docs/advanced/aot/
235 \fB--attach=[options]\fR
236 Currently the only option supported by this command line argument is
237 \fBdisable\fR which disables the attach functionality.
239 \fB--config filename\fR
240 Load the specified configuration file instead of the default one(s).
241 The default files are /etc/mono/config and ~/.mono/config or the file
242 specified in the MONO_CONFIG environment variable, if set. See the
243 mono-config(5) man page for details on the format of this file.
245 \fB--debugger-agent=[options]\fR
246 This instructs the Mono runtime to
247 start a debugging agent inside the Mono runtime and connect it to a
248 client user interface will control the Mono process.
249 This option is typically used by IDEs, like the MonoDevelop IDE.
251 The configuration is specified using one of more of the following options:
257 Use this option to specify the IP address where your debugger client is
262 Specifies the diagnostics log level for
266 Used to specify the file where the log will be stored, it defaults to
270 Defaults to no, with the default option Mono will actively connect to the
271 host/port configured with the \fBaddress\fR option. If you set it to 'y', it
272 instructs the Mono runtime to start debugging in server mode, where Mono
273 actively waits for the debugger front end to connect to the Mono process.
274 Mono will print out to stdout the IP address and port where it is listening.
277 If set to yes, Mono will call \fBsetpgid(0, 0)\fB on startup, if that function
278 is available on the system. This is useful for ensuring that signals delivered
279 to a process that is executing the debuggee are not propagated to the debuggee,
280 e.g. when Ctrl-C sends \fBSIGINT\fB to the \fBsdb\fB tool.
283 Defaults to yes, with the default option Mono will suspend the vm on startup
284 until it connects successfully to a debugger front end. If you set it to 'n', in
285 conjunction with \fBserver=y\fR, it instructs the Mono runtime to run as normal,
286 while caching metadata to send to the debugger front end on connection..
288 .I transport=transport_name
290 This is used to specify the transport that the debugger will use to
291 communicate. It must be specified and currently requires this to
297 Configures the virtual machine to be better suited for desktop
298 applications. Currently this sets the GC system to avoid expanding
299 the heap as much as possible at the expense of slowing down garbage
303 This is an experimental flag that instructs the Mono runtime to not
304 generate any code at runtime and depend exclusively on the code
305 generated from using mono --aot=full previously. This is useful for
306 platforms that do not permit dynamic code generation.
308 Notice that this feature will abort execution at runtime if a codepath
309 in your program, or Mono's class libraries attempts to generate code
310 dynamically. You should test your software upfront and make sure that
311 you do not use any dynamic features.
313 \fB--gc=boehm\fR, \fB--gc=sgen\fR
314 Selects the Garbage Collector engine for Mono to use, Boehm or SGen.
315 Currently this merely ensures that you are running either the
316 \fImono\fR or \fImono-sgen\fR commands. This flag can be set in the
317 \fBMONO_ENV_OPTIONS\fR environment variable to force all of your child
318 processes to use one particular kind of GC with the Mono runtime.
320 \fB--arch=32\fR, \fB--arch=64\fR
321 (Mac OS X only): Selects the bitness of the Mono binary used, if
322 available. If the binary used is already for the selected bitness, nothing
323 changes. If not, the execution switches to a binary with the selected
324 bitness suffix installed side by side (for example, '/bin/mono --arch=64'
325 will switch to '/bin/mono64' iff '/bin/mono' is a 32-bit build).
327 \fB--help\fR, \fB-h\fR
328 Displays usage instructions.
331 If the Mono runtime has been compiled with LLVM support (not available
332 in all configurations), Mono will use the LLVM optimization and code
333 generation engine to JIT or AOT compile.
335 For more information, consult: http://www.mono-project.com/docs/advanced/mono-llvm/
338 When using a Mono that has been compiled with LLVM support, it forces
339 Mono to fallback to its JIT engine and not use the LLVM backend.
341 \fB--optimize=MODE\fR, \fB-O=MODE\fR
342 MODE is a comma separated list of optimizations. They also allow
343 optimizations to be turned off by prefixing the optimization name with
346 In general, Mono has been tuned to use the default set of flags,
347 before using these flags for a deployment setting, you might want to
348 actually measure the benefits of using them.
350 The following optimization flags are implemented in the core engine:
352 abcrem Array bound checks removal
353 all Turn on all optimizations
354 aot Usage of Ahead Of Time compiled code
355 branch Branch optimizations
356 cfold Constant folding
357 cmov Conditional moves [arch-dependency]
358 deadce Dead code elimination
359 consprop Constant propagation
360 copyprop Copy propagation
361 fcmov Fast x86 FP compares [arch-dependency]
362 float32 Perform 32-bit float arithmetic using 32-bit operations
363 gshared Enable generic code sharing.
364 inline Inline method calls
365 intrins Intrinsic method implementations
366 linears Linear scan global reg allocation
367 leaf Leaf procedures optimizations
368 loop Loop related optimizations
369 peephole Peephole postpass
370 precomp Precompile all methods before executing Main
371 sched Instruction scheduling
372 shared Emit per-domain code
373 sse2 SSE2 instructions on x86 [arch-dependency]
374 tailc Tail recursion and tail calls
377 For example, to enable all the optimization but dead code
378 elimination and inlining, you can use:
380 -O=all,-deadce,-inline
383 The flags that are flagged with [arch-dependency] indicate that the
384 given option if used in combination with Ahead of Time compilation
385 (--aot flag) would produce pre-compiled code that will depend on the
386 current CPU and might not be safely moved to another computer.
390 The following optimizations are supported
393 Requests that the runtime performn 32-bit floating point operations
394 using only 32-bits. By default the Mono runtime tries to use the
395 highest precision available for floating point operations, but while
396 this might render better results, the code might run slower. This
397 options also affects the code generated by the LLVM backend.
400 Controls whether the runtime should attempt to inline (the default),
401 or not inline methods invocations
405 \fB--runtime=VERSION\fR
406 Mono supports different runtime versions. The version used depends on the program
407 that is being run or on its configuration file (named program.exe.config). This option
408 can be used to override such autodetection, by forcing a different runtime version
409 to be used. Note that this should only be used to select a later compatible runtime
410 version than the one the program was compiled against. A typical usage is for
411 running a 1.1 program on a 2.0 version:
413 mono --runtime=v2.0.50727 program.exe
416 \fB--security\fR, \fB--security=mode\fR
417 Activate the security manager, a currently experimental feature in
418 Mono and it is OFF by default. The new code verifier can be enabled
419 with this option as well.
423 Using security without parameters is equivalent as calling it with the
426 The following modes are supported:
429 Enables the core-clr security system, typically used for
430 Moonlight/Silverlight applications. It provides a much simpler
431 security system than CAS, see http://www.mono-project.com/docs/web/moonlight/
432 for more details and links to the descriptions of this new system.
435 Enables the new verifier and performs basic verification for code
436 validity. In this mode, unsafe code and P/Invoke are allowed. This
437 mode provides a better safety guarantee but it is still possible
438 for managed code to crash Mono.
441 Enables the new verifier and performs full verification of the code
442 being executed. It only allows verifiable code to be executed.
443 Unsafe code is not allowed but P/Invoke is. This mode should
444 not allow managed code to crash mono. The verification is not as
445 strict as ECMA 335 standard in order to stay compatible with the MS
448 The security system acts on user code: code contained in mscorlib or
449 the global assembly cache is always trusted.
454 Configures the virtual machine to be better suited for server
455 operations (currently, allows a heavier threadpool initialization).
458 Verifies mscorlib and assemblies in the global
459 assembly cache for valid IL, and all user code for IL
462 This is different from \fB--security\fR's verifiable
463 or validil in that these options only check user code and skip
464 mscorlib and assemblies located on the global assembly cache.
466 \fB-V\fR, \fB--version\fR
467 Prints JIT version information (system configuration, release number
468 and branch names if available).
471 .SH DEVELOPMENT OPTIONS
472 The following options are used to help when developing a JITed application.
474 \fB--debug\fR, \fB--debug=OPTIONS\fR
475 Turns on the debugging mode in the runtime. If an assembly was
476 compiled with debugging information, it will produce line number
477 information for stack traces.
481 The optional OPTIONS argument is a comma separated list of debugging
482 options. These options are turned off by default since they generate
483 much larger and slower code at runtime.
485 The following options are supported:
488 Produces a detailed error when throwing a InvalidCastException. This
489 option needs to be enabled as this generates more verbose code at
493 Disable some JIT optimizations which are usually only disabled when
494 running inside the debugger. This can be helpful if you want to attach
495 to the running process with mdb.
498 Generate and register debugging information with gdb. This is only supported on some
499 platforms, and only when using gdb 7.0 or later.
503 \fB--profile[=profiler[:profiler_args]]\fR
504 Turns on profiling. For more information about profiling applications
505 and code coverage see the sections "PROFILING" and "CODE COVERAGE"
508 This option can be used multiple times, each time will load an
509 additional profiler. This allows developers to use modules that
510 extend the JIT through the Mono profiling interface.
512 \fB--trace[=expression]\fR
513 Shows method names as they are invoked. By default all methods are
516 The trace can be customized to include or exclude methods, classes or
517 assemblies. A trace expression is a comma separated list of targets,
518 each target can be prefixed with a minus sign to turn off a particular
519 target. The words `program', `all' and `disabled' have special
520 meaning. `program' refers to the main program being executed, and
521 `all' means all the method calls.
523 The `disabled' option is used to start up with tracing disabled. It
524 can be enabled at a later point in time in the program by sending the
525 SIGUSR2 signal to the runtime.
527 Assemblies are specified by their name, for example, to trace all
528 calls in the System assembly, use:
531 mono --trace=System app.exe
534 Classes are specified with the T: prefix. For example, to trace all
535 calls to the System.String class, use:
538 mono --trace=T:System.String app.exe
541 And individual methods are referenced with the M: prefix, and the
542 standard method notation:
545 mono --trace=M:System.Console:WriteLine app.exe
548 Exceptions can also be traced, it will cause a stack trace to be
549 printed every time an exception of the specified type is thrown.
550 The exception type can be specified with or without the namespace,
551 and to trace all exceptions, specify 'all' as the type name.
554 mono --trace=E:System.Exception app.exe
557 As previously noted, various rules can be specified at once:
560 mono --trace=T:System.String,T:System.Random app.exe
563 You can exclude pieces, the next example traces calls to
564 System.String except for the System.String:Concat method.
567 mono --trace=T:System.String,-M:System.String:Concat
570 You can trace managed to unmanaged transitions using
571 the wrapper qualifier:
574 mono --trace=wrapper app.exe
577 Finally, namespaces can be specified using the N: prefix:
580 mono --trace=N:System.Xml
584 \fB--no-x86-stack-align\fR
585 Don't align stack frames on the x86 architecture. By default, Mono
586 aligns stack frames to 16 bytes on x86, so that local floating point
587 and SIMD variables can be properly aligned. This option turns off the
588 alignment, which usually saves one intruction per call, but might
589 result in significantly lower floating point and SIMD performance.
592 Generate a JIT method map in a /tmp/perf-PID.map file. This file is then
593 used, for example, by the perf tool included in recent Linux kernels.
594 Each line in the file has:
597 HEXADDR HEXSIZE methodname
600 Currently this option is only supported on Linux.
601 .SH JIT MAINTAINER OPTIONS
602 The maintainer options are only used by those developing the runtime
603 itself, and not typically of interest to runtime users or developers.
606 Inserts a breakpoint before the method whose name is `method'
607 (namespace.class:methodname). Use `Main' as method name to insert a
608 breakpoint on the application's main method. You can use it also with
609 generics, for example "System.Collections.Generic.Queue`1:Peek"
612 Inserts a breakpoint on exceptions. This allows you to debug your
613 application with a native debugger when an exception is thrown.
616 This compiles a method (namespace.name:methodname), this is used for
617 testing the compiler performance or to examine the output of the code
621 Compiles all the methods in an assembly. This is used to test the
622 compiler performance or to examine the output of the code generator
624 \fB--graph=TYPE METHOD\fR
625 This generates a postscript file with a graph with the details about
626 the specified method (namespace.name:methodname). This requires `dot'
627 and ghostview to be installed (it expects Ghostview to be called
630 The following graphs are available:
632 cfg Control Flow Graph (CFG)
634 code CFG showing code
635 ssa CFG showing code after SSA translation
636 optcode CFG showing code after IR optimizations
639 Some graphs will only be available if certain optimizations are turned
643 Instruct the runtime on the number of times that the method specified
644 by --compile (or all the methods if --compileall is used) to be
645 compiled. This is used for testing the code generator performance.
648 Displays information about the work done by the runtime during the
649 execution of an application.
651 \fB--wapi=hps|semdel\fR
652 Perform maintenance of the process shared data.
654 semdel will delete the global semaphore.
656 hps will list the currently used handles.
658 \fB-v\fR, \fB--verbose\fR
659 Increases the verbosity level, each time it is listed, increases the
660 verbosity level to include more information (including, for example,
661 a disassembly of the native code produced, code selector info etc.).
663 The Mono runtime allows external processes to attach to a running
664 process and load assemblies into the running program. To attach to
665 the process, a special protocol is implemented in the Mono.Management
668 With this support it is possible to load assemblies that have an entry
669 point (they are created with -target:exe or -target:winexe) to be
670 loaded and executed in the Mono process.
672 The code is loaded into the root domain, and it starts execution on
673 the special runtime attach thread. The attached program should
674 create its own threads and return after invocation.
676 This support allows for example debugging applications by having the
677 csharp shell attach to running processes.
679 The mono runtime includes a profiler that can be used to explore
680 various performance related problems in your application. The
681 profiler is activated by passing the --profile command line argument
682 to the Mono runtime, the format is:
685 --profile[=profiler[:profiler_args]]
688 Mono has a built-in profiler called 'default' (and is also the default
689 if no arguments are specified), but developers can write custom
690 profilers, see the section "CUSTOM PROFILERS" for more details.
694 is not specified, the default profiler is used.
698 is a profiler-specific string of options for the profiler itself.
700 The default profiler accepts the following options 'alloc' to profile
701 memory consumption by the application; 'time' to profile the time
702 spent on each routine; 'jit' to collect time spent JIT-compiling methods
703 and 'stat' to perform sample statistical profiling.
704 If no options are provided the default is 'alloc,time,jit'.
707 profile data is printed to stdout: to change this, use the 'file=filename'
708 option to output the data to filename.
713 mono --profile program.exe
717 That will run the program with the default profiler and will do time
718 and allocation profiling.
722 mono --profile=default:stat,alloc,file=prof.out program.exe
725 Will do sample statistical profiling and allocation profiling on
726 program.exe. The profile data is put in prof.out.
728 Note that the statistical profiler has a very low overhead and should
729 be the preferred profiler to use (for better output use the full path
730 to the mono binary when running and make sure you have installed the
731 addr2line utility that comes from the binutils package).
733 This is the most advanced profiler.
735 The Mono \f[I]log\f[] profiler can be used to collect a lot of
736 information about a program running in the Mono runtime.
737 This data can be used (both while the process is running and later)
738 to do analyses of the program behaviour, determine resource usage,
739 performance issues or even look for particular execution patterns.
741 This is accomplished by logging the events provided by the Mono
742 runtime through the profiling interface and periodically writing
743 them to a file which can be later inspected with the mprof-report(1)
746 More information about how to use the log profiler is available on the
747 mprof-report(1) page.
749 Mono provides a mechanism for loading other profiling modules which in
750 the form of shared libraries. These profiling modules can hook up to
751 various parts of the Mono runtime to gather information about the code
754 To use a third party profiler you must pass the name of the profiler
758 mono --profile=custom program.exe
762 In the above sample Mono will load the user defined profiler from the
763 shared library `mono-profiler-custom.so'. This profiler module must
764 be on your dynamic linker library path.
766 A list of other third party profilers is available from Mono's web
767 site (www.mono-project.com/docs/advanced/performance-tips/)
769 Custom profiles are written as shared libraries. The shared library
770 must be called `mono-profiler-NAME.so' where `NAME' is the name of
773 For a sample of how to write your own custom profiler look in the
774 Mono source tree for in the samples/profiler.c.
776 Mono ships with a code coverage module. This module is activated by
777 using the Mono --profile=cov option. The format is:
778 \fB--profile=cov[:assembly-name[/namespace]] test-suite.exe\fR
780 By default code coverage will default to all the assemblies loaded,
781 you can limit this by specifying the assembly name, for example to
782 perform code coverage in the routines of your program use, for example
783 the following command line limits the code coverage to routines in the
787 mono --profile=cov:demo demo.exe
793 does not include the extension.
795 You can further restrict the code coverage output by specifying a
799 mono --profile=cov:demo/My.Utilities demo.exe
803 Which will only perform code coverage in the given assembly and
806 Typical output looks like this:
809 Not covered: Class:.ctor ()
810 Not covered: Class:A ()
811 Not covered: Driver:.ctor ()
812 Not covered: Driver:method ()
813 Partial coverage: Driver:Main ()
818 The offsets displayed are IL offsets.
820 A more powerful coverage tool is available in the module `monocov'.
821 See the monocov(1) man page for details.
823 To debug managed applications, you can use the
825 command, a command line debugger.
827 It is possible to obtain a stack trace of all the active threads in
828 Mono by sending the QUIT signal to Mono, you can do this from the
829 command line, like this:
835 Where pid is the Process ID of the Mono process you want to examine.
836 The process will continue running afterwards, but its state is not
840 this is a last-resort mechanism for debugging applications and should
841 not be used to monitor or probe a production application. The
842 integrity of the runtime after sending this signal is not guaranteed
843 and the application might crash or terminate at any given point
846 The \fB--debug=casts\fR option can be used to get more detailed
847 information for Invalid Cast operations, it will provide information
848 about the types involved.
850 You can use the MONO_LOG_LEVEL and MONO_LOG_MASK environment variables
851 to get verbose debugging output about the execution of your
852 application within Mono.
856 environment variable if set, the logging level is changed to the set
857 value. Possible values are "error", "critical", "warning", "message",
858 "info", "debug". The default value is "error". Messages with a logging
859 level greater then or equal to the log level will be printed to
862 Use "info" to track the dynamic loading of assemblies.
867 environment variable to limit the extent of the messages you get:
868 If set, the log mask is changed to the set value. Possible values are
869 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
870 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
871 "security" (e.g. Moonlight CoreCLR support) and "all".
872 The default value is "all". Changing the mask value allows you to display only
873 messages for a certain component. You can use multiple masks by comma
874 separating them. For example to see config file messages and assembly loader
875 messages set you mask to "asm,cfg".
877 The following is a common use to track down problems with P/Invoke:
880 $ MONO_LOG_LEVEL="debug" MONO_LOG_MASK="dll" mono glue.exe
884 .SH DEBUGGING WITH LLDB
885 If you are using LLDB, you can use the
887 script to print some internal data structures with it. To use this,
892 command script import $PREFIX/lib/mono/lldb/mono.py
895 Where $PREFIX is the prefix value that you used when you configured
896 Mono (typically /usr).
898 Once this is done, then you can inspect some Mono Runtime data structures,
903 (MonoMethod *) $0 = 0x05026ac0 [mscorlib]System.OutOfMemoryException:.ctor()
906 Mono's XML serialization engine by default will use a reflection-based
907 approach to serialize which might be slow for continuous processing
908 (web service applications). The serialization engine will determine
909 when a class must use a hand-tuned serializer based on a few
910 parameters and if needed it will produce a customized C# serializer
911 for your types at runtime. This customized serializer then gets
912 dynamically loaded into your application.
914 You can control this with the MONO_XMLSERIALIZER_THS environment
917 The possible values are
919 to disable the use of a C# customized
920 serializer, or an integer that is the minimum number of uses before
921 the runtime will produce a custom serializer (0 will produce a
922 custom serializer on the first access, 50 will produce a serializer on
923 the 50th use). Mono will fallback to an interpreted serializer if the
924 serializer generation somehow fails. This behavior can be disabled
925 by setting the option
927 (for example: MONO_XMLSERIALIZER_THS=0,nofallback).
928 .SH ENVIRONMENT VARIABLES
931 Turns off the garbage collection in Mono. This should be only used
932 for debugging purposes
935 When Mono is compiled with LLVM support, this instructs the runtime to
936 stop using LLVM after the specified number of methods are JITed.
937 This is a tool used in diagnostics to help isolate problems in the
938 code generation backend. For example \fBLLVM_COUNT=10\fR would only
939 compile 10 methods with LLVM and then switch to the Mono JIT engine.
940 \fBLLVM_COUNT=0\fR would disable the LLVM engine altogether.
943 If set, this variable will instruct Mono to ahead-of-time compile new
944 assemblies on demand and store the result into a cache in
947 \fBMONO_ASPNET_INHIBIT_SETTINGSMAP\fR
948 Mono contains a feature which allows modifying settings in the .config files shipped
949 with Mono by using config section mappers. The mappers and the mapping rules are
950 defined in the $prefix/etc/mono/2.0/settings.map file and, optionally, in the
951 settings.map file found in the top-level directory of your ASP.NET application.
952 Both files are read by System.Web on application startup, if they are found at the
953 above locations. If you don't want the mapping to be performed you can set this
954 variable in your environment before starting the application and no action will
957 \fBMONO_ASPNET_WEBCONFIG_CACHESIZE\fR
958 Mono has a cache of ConfigSection objects for speeding up WebConfigurationManager
959 queries. Its default size is 100 items, and when more items are needed, cache
960 evictions start happening. If evictions are too frequent this could impose
961 unnecessary overhead, which could be avoided by using this environment variable
962 to set up a higher cache size (or to lower memory requirements by decreasing it).
964 \fBMONO_CAIRO_DEBUG_DISPOSE\fR
965 If set, causes Mono.Cairo to collect stack traces when objects are allocated,
966 so that the finalization/Dispose warnings include information about the
970 If set, this variable overrides the default system configuration directory
971 ($PREFIX/etc). It's used to locate machine.config file.
974 Sets the style of COM interop. If the value of this variable is "MS"
975 Mono will use string marhsalling routines from the liboleaut32 for the
976 BSTR type library, any other values will use the mono-builtin BSTR
980 If set, this variable overrides the default runtime configuration file
981 ($PREFIX/etc/mono/config). The --config command line options overrides the
982 environment variable.
985 Override the automatic cpu detection mechanism. Currently used only on arm.
986 The format of the value is as follows:
992 where V is the architecture number 4, 5, 6, 7 and the options can be currently be
993 "thumb" or "thumb2". Example:
996 MONO_CPU_ARCH="armv4 thumb" mono ...
1000 \fBMONO_ARM_FORCE_SOFT_FLOAT\fR
1001 When Mono is built with a soft float fallback on ARM and this variable is set to
1002 "1", Mono will always emit soft float code, even if a VFP unit is detected.
1004 \fBMONO_DISABLE_AIO\fR
1005 If set, tells mono NOT to attempt using native asynchronous I/O services. In
1006 that case, a default select/poll implementation is used. Currently only epoll()
1009 \fBMONO_DISABLE_MANAGED_COLLATION\fR
1010 If this environment variable is `yes', the runtime uses unmanaged
1011 collation (which actually means no culture-sensitive collation). It
1012 internally disables managed collation functionality invoked via the
1013 members of System.Globalization.CompareInfo class. Collation is
1016 \fBMONO_DISABLE_SHM\fR
1017 Unix only: If set, disables the shared memory files used for
1018 cross-process handles: process have only private handles. This means
1019 that process and thread handles are not available to other processes,
1020 and named mutexes, named events and named semaphores are not visible
1023 This is can also be enabled by default by passing the
1024 "--disable-shared-handles" option to configure.
1026 This is the default from mono 2.8 onwards.
1028 \fBMONO_DISABLE_SHARED_AREA\fR
1029 Unix only: If set, disable usage of shared memory for exposing
1030 performance counters. This means it will not be possible to both
1031 externally read performance counters from this processes or read
1032 those of external processes.
1035 When set, enables the use of a fully managed DNS resolver instead of the
1036 regular libc functions. This resolver performs much better when multiple
1037 queries are run in parallel.
1039 Note that /etc/nsswitch.conf will be ignored.
1041 \fBMONO_EGD_SOCKET\fR
1042 For platforms that do not otherwise have a way of obtaining random bytes
1043 this can be set to the name of a file system socket on which an egd or
1044 prngd daemon is listening.
1046 \fBMONO_ENABLE_SHM\fR
1047 Unix only: Enable support for cross-process handles. Cross-process
1048 handles are used to expose process handles, thread handles, named
1049 mutexes, named events and named semaphores across Unix processes.
1051 \fBMONO_ENV_OPTIONS\fR
1052 This environment variable allows you to pass command line arguments to
1053 a Mono process through the environment. This is useful for example
1054 to force all of your Mono processes to use LLVM or SGEN without having
1055 to modify any launch scripts.
1057 \fBMONO_ENV_OPTIONS\fR
1058 Used to pass extra options to the debugger agent in the runtime, as they were passed
1059 using --debugger-agent=.
1061 \fBMONO_EVENTLOG_TYPE\fR
1062 Sets the type of event log provider to use (for System.Diagnostics.EventLog).
1064 Possible values are:
1069 Persists event logs and entries to the local file system.
1071 The directory in which to persist the event logs, event sources and entries
1072 can be specified as part of the value.
1074 If the path is not explicitly set, it defaults to "/var/lib/mono/eventlog"
1075 on unix and "%APPDATA%\mono\eventlog" on Windows.
1080 Uses the native win32 API to write events and registers event logs and
1081 event sources in the registry. This is only available on Windows.
1083 On Unix, the directory permission for individual event log and event source
1084 directories is set to 777 (with +t bit) allowing everyone to read and write
1085 event log entries while only allowing entries to be deleted by the user(s)
1090 Silently discards any events.
1093 The default is "null" on Unix (and versions of Windows before NT), and
1094 "win32" on Windows NT (and higher).
1097 \fBMONO_EXTERNAL_ENCODINGS\fR
1098 If set, contains a colon-separated list of text encodings to try when
1099 turning externally-generated text (e.g. command-line arguments or
1100 filenames) into Unicode. The encoding names come from the list
1101 provided by iconv, and the special case "default_locale" which refers
1102 to the current locale's default encoding.
1104 When reading externally-generated text strings UTF-8 is tried first,
1105 and then this list is tried in order with the first successful
1106 conversion ending the search. When writing external text (e.g. new
1107 filenames or arguments to new processes) the first item in this list
1108 is used, or UTF-8 if the environment variable is not set.
1110 The problem with using MONO_EXTERNAL_ENCODINGS to process your
1111 files is that it results in a problem: although its possible to get
1112 the right file name it is not necessarily possible to open the file.
1113 In general if you have problems with encodings in your filenames you
1114 should use the "convmv" program.
1116 \fBMONO_GC_PARAMS\fR
1117 When using Mono with the SGen garbage collector this variable controls
1118 several parameters of the collector. The variable's value is a comma
1119 separated list of words.
1123 \fBmax-heap-size=\fIsize\fR
1124 Sets the maximum size of the heap. The size is specified in bytes and must
1125 be a power of two. The suffixes `k', `m' and `g' can be used to
1126 specify kilo-, mega- and gigabytes, respectively. The limit is the sum
1127 of the nursery, major heap and large object heap. Once the limit is reached
1128 the application will receive OutOfMemoryExceptions when trying to allocate.
1129 Not the full extent of memory set in max-heap-size could be available to
1130 satisfy a single allocation due to internal fragmentation. By default heap
1131 limits is disabled and the GC will try to use all available memory.
1133 \fBnursery-size=\fIsize\fR
1134 Sets the size of the nursery. The size is specified in bytes and must
1135 be a power of two. The suffixes `k', `m' and `g' can be used to
1136 specify kilo-, mega- and gigabytes, respectively. The nursery is the
1137 first generation (of two). A larger nursery will usually speed up the
1138 program but will obviously use more memory. The default nursery size
1141 \fBmajor=\fIcollector\fR Specifies which major collector to use.
1142 Options are `marksweep' for the Mark&Sweep collector, and
1143 `marksweep-conc' for concurrent Mark&Sweep. The non-concurrent
1144 Mark&Sweep collector is the default.
1146 \fBsoft-heap-limit=\fIsize\fR
1147 Once the heap size gets larger than this size, ignore what the default
1148 major collection trigger metric says and only allow four nursery size's
1149 of major heap growth between major collections.
1151 \fBevacuation-threshold=\fIthreshold\fR
1152 Sets the evacuation threshold in percent. This option is only available
1153 on the Mark&Sweep major collectors. The value must be an
1154 integer in the range 0 to 100. The default is 66. If the sweep phase of
1155 the collection finds that the occupancy of a specific heap block type is
1156 less than this percentage, it will do a copying collection for that block
1157 type in the next major collection, thereby restoring occupancy to close
1158 to 100 percent. A value of 0 turns evacuation off.
1160 \fB(no-)lazy-sweep\fR
1161 Enables or disables lazy sweep for the Mark&Sweep collector. If
1162 enabled, the sweeping of individual major heap blocks is done
1163 piecemeal whenever the need arises, typically during nursery
1164 collections. Lazy sweeping is enabled by default.
1166 \fB(no-)concurrent-sweep\fR
1167 Enables or disables concurrent sweep for the Mark&Sweep collector. If
1168 enabled, the iteration of all major blocks to determine which ones can
1169 be freed and which ones have to be kept and swept, is done
1170 concurrently with the running program. Concurrent sweeping is enabled
1173 \fBstack-mark=\fImark-mode\fR
1174 Specifies how application threads should be scanned. Options are
1175 `precise` and `conservative`. Precise marking allow the collector
1176 to know what values on stack are references and what are not.
1177 Conservative marking threats all values as potentially references
1178 and leave them untouched. Precise marking reduces floating garbage
1179 and can speed up nursery collection and allocation rate, it has
1180 the downside of requiring a significant extra memory per compiled
1181 method. The right option, unfortunately, requires experimentation.
1183 \fBsave-target-ratio=\fIratio\fR
1184 Specifies the target save ratio for the major collector. The collector
1185 lets a given amount of memory to be promoted from the nursery due to
1186 minor collections before it triggers a major collection. This amount
1187 is based on how much memory it expects to free. It is represented as
1188 a ratio of the size of the heap after a major collection.
1189 Valid values are between 0.1 and 2.0. The default is 0.5.
1190 Smaller values will keep the major heap size smaller but will trigger
1191 more major collections. Likewise, bigger values will use more memory
1192 and result in less frequent major collections.
1193 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1195 \fBdefault-allowance-ratio=\fIratio\fR
1196 Specifies the default allocation allowance when the calculated size
1197 is too small. The allocation allowance is how much memory the collector
1198 let be promoted before triggered a major collection.
1199 It is a ratio of the nursery size.
1200 Valid values are between 1.0 and 10.0. The default is 4.0.
1201 Smaller values lead to smaller heaps and more frequent major collections.
1202 Likewise, bigger values will allow the heap to grow faster but use
1203 more memory when it reaches a stable size.
1204 This option is EXPERIMENTAL, so it might disappear in later versions of mono.
1206 \fBminor=\fIminor-collector\fR
1207 Specifies which minor collector to use. Options are 'simple' which
1208 promotes all objects from the nursery directly to the old generation
1209 and 'split' which lets object stay longer on the nursery before promoting.
1211 \fBalloc-ratio=\fIratio\fR
1212 Specifies the ratio of memory from the nursery to be use by the alloc space.
1213 This only can only be used with the split minor collector.
1214 Valid values are integers between 1 and 100. Default is 60.
1216 \fBpromotion-age=\fIage\fR
1217 Specifies the required age of an object must reach inside the nursery before
1218 been promoted to the old generation. This only can only be used with the
1219 split minor collector.
1220 Valid values are integers between 1 and 14. Default is 2.
1222 \fB(no-)cementing\fR
1223 Enables or disables cementing. This can dramatically shorten nursery
1224 collection times on some benchmarks where pinned objects are referred
1225 to from the major heap.
1227 \fBallow-synchronous-major\fR
1228 This forbids the major collector from performing synchronous major collections.
1229 The major collector might want to do a synchronous collection due to excessive
1230 fragmentation. Disabling this might trigger OutOfMemory error in situations that
1231 would otherwise not happen.
1236 When using Mono with the SGen garbage collector this environment
1237 variable can be used to turn on various debugging features of the
1238 collector. The value of this variable is a comma separated list of
1239 words. Do not use these options in production.
1244 Sets the debug level to the specified number.
1246 \fBprint-allowance\fR
1247 After each major collection prints memory consumption for before and
1248 after the collection and the allowance for the minor collector, i.e. how
1249 much the heap is allowed to grow from minor collections before the next
1250 major collection is triggered.
1253 Gathers statistics on the classes whose objects are pinned in the
1254 nursery and for which global remset entries are added. Prints those
1255 statistics when shutting down.
1257 \fBcollect-before-allocs\fR
1259 \fBcheck-at-minor-collections\fR
1260 This performs a consistency check on minor collections and also clears
1261 the nursery at collection time, instead of the default, when buffers
1262 are allocated (clear-at-gc). The consistency check ensures that
1263 there are no major to minor references that are not on the remembered
1266 \fBmod-union-consistency-check\fR
1267 Checks that the mod-union cardtable is consistent before each
1268 finishing major collection pause. This check is only applicable to
1269 concurrent major collectors.
1271 \fBcheck-mark-bits\fR
1272 Checks that mark bits in the major heap are consistent at the end of
1273 each major collection. Consistent mark bits mean that if an object is
1274 marked, all objects that it had references to must also be marked.
1276 \fBcheck-nursery-pinned\fR
1277 After nursery collections, and before starting concurrent collections,
1278 check whether all nursery objects are pinned, or not pinned -
1279 depending on context. Does nothing when the split nursery collector
1282 \fBxdomain-checks\fR
1283 Performs a check to make sure that no references are left to an
1286 \fBclear-at-tlab-creation\fR
1287 Clears the nursery incrementally when the thread local allocation
1288 buffers (TLAB) are created. The default setting clears the whole
1291 \fBdebug-clear-at-tlab-creation\fR
1292 Clears the nursery incrementally when the thread local allocation
1293 buffers (TLAB) are created, but at GC time fills it with the byte
1294 `0xff`, which should result in a crash more quickly if
1295 `clear-at-tlab-creation` doesn't work properly.
1298 This clears the nursery at GC time instead of doing it when the thread
1299 local allocation buffer (TLAB) is created. The default is to clear
1300 the nursery at TLAB creation time.
1303 Don't do minor collections. If the nursery is full, a major collection
1304 is triggered instead, unless it, too, is disabled.
1307 Don't do major collections.
1309 \fBconservative-stack-mark\fR
1310 Forces the GC to scan the stack conservatively, even if precise
1311 scanning is available.
1313 \fBno-managed-allocator\fR
1314 Disables the managed allocator.
1316 \fBcheck-scan-starts\fR
1317 If set, does a plausibility check on the scan_starts before and after each collection
1319 \fBverify-nursery-at-minor-gc\fR
1320 If set, does a complete object walk of the nursery at the start of each minor collection.
1322 \fBdump-nursery-at-minor-gc\fR
1323 If set, dumps the contents of the nursery at the start of each minor collection. Requires
1324 verify-nursery-at-minor-gc to be set.
1326 \fBheap-dump=\fIfile\fR
1327 Dumps the heap contents to the specified file. To visualize the
1328 information, use the mono-heapviz tool.
1330 \fBbinary-protocol=\fIfile\fR
1331 Outputs the debugging output to the specified file. For this to
1332 work, Mono needs to be compiled with the BINARY_PROTOCOL define on
1333 sgen-gc.c. You can then use this command to explore the output
1335 sgen-grep-binprot 0x1234 0x5678 < file
1338 \fBnursery-canaries\fR
1339 If set, objects allocated in the nursery are suffixed with a canary (guard)
1340 word, which is checked on each minor collection. Can be used to detect/debug
1341 heap corruption issues.
1344 \fBdo-not-finalize(=\fIclasses\fB)\fR
1345 If enabled, finalizers will not be run. Everything else will be
1346 unaffected: finalizable objects will still be put into the
1347 finalization queue where they survive until they're scheduled to
1348 finalize. Once they're not in the queue anymore they will be
1349 collected regularly. If a list of comma-separated class names is
1350 given, only objects from those classes will not be finalized.
1353 \fBlog-finalizers\fR
1354 Log verbosely around the finalization process to aid debugging.
1358 \fBMONO_GAC_PREFIX\fR
1359 Provides a prefix the runtime uses to look for Global Assembly Caches.
1360 Directories are separated by the platform path separator (colons on
1361 unix). MONO_GAC_PREFIX should point to the top directory of a prefixed
1362 install. Or to the directory provided in the gacutil /gacdir command. Example:
1363 .B /home/username/.mono:/usr/local/mono/
1366 Enables some filename rewriting support to assist badly-written
1367 applications that hard-code Windows paths. Set to a colon-separated
1368 list of "drive" to strip drive letters, or "case" to do
1369 case-insensitive file matching in every directory in a path. "all"
1370 enables all rewriting methods. (Backslashes are always mapped to
1371 slashes if this variable is set to a valid option).
1374 For example, this would work from the shell:
1377 MONO_IOMAP=drive:case
1381 If you are using mod_mono to host your web applications, you can use
1384 directive instead, like this:
1387 MonoIOMAP <appalias> all
1390 See mod_mono(8) for more details.
1392 Additionally. Mono includes a profiler module which allows one to track what
1393 adjustements to file paths IOMAP code needs to do. The tracking code reports
1394 the managed location (full stack trace) from which the IOMAP-ed call was made and,
1395 on process exit, the locations where all the IOMAP-ed strings were created in
1396 managed code. The latter report is only approximate as it is not always possible
1397 to estimate the actual location where the string was created. The code uses simple
1398 heuristics - it analyzes stack trace leading back to the string allocation location
1399 and ignores all the managed code which lives in assemblies installed in GAC as well as in the
1400 class libraries shipped with Mono (since they are assumed to be free of case-sensitivity
1401 issues). It then reports the first location in the user's code - in most cases this will be
1402 the place where the string is allocated or very close to the location. The reporting code
1403 is implemented as a custom profiler module (see the "PROFILING" section) and can be loaded
1404 in the following way:
1409 mono --profile=iomap yourapplication.exe
1412 Note, however, that Mono currently supports only one profiler module
1416 When Mono is using the LLVM code generation backend you can use this
1417 environment variable to pass code generation options to the LLVM
1420 \fBMONO_MANAGED_WATCHER\fR
1421 If set to "disabled", System.IO.FileSystemWatcher will use a file watcher
1422 implementation which silently ignores all the watching requests.
1423 If set to any other value, System.IO.FileSystemWatcher will use the default
1424 managed implementation (slow). If unset, mono will try to use inotify, FAM,
1425 Gamin, kevent under Unix systems and native API calls on Windows, falling
1426 back to the managed implementation on error.
1428 \fBMONO_MESSAGING_PROVIDER\fR
1429 Mono supports a plugin model for its implementation of System.Messaging making
1430 it possible to support a variety of messaging implementations (e.g. AMQP, ActiveMQ).
1431 To specify which messaging implementation is to be used the evironement variable
1432 needs to be set to the full class name for the provider. E.g. to use the RabbitMQ based
1433 AMQP implementation the variable should be set to:
1436 Mono.Messaging.RabbitMQ.RabbitMQMessagingProvider,Mono.Messaging.RabbitMQ
1439 If set causes the mono process to be bound to a single processor. This may be
1440 useful when debugging or working around race conditions.
1443 Disable inlining of thread local accesses. Try setting this if you get a segfault
1444 early on in the execution of mono.
1447 Provides a search path to the runtime where to look for library
1448 files. This is a tool convenient for debugging applications, but
1449 should not be used by deployed applications as it breaks the assembly
1450 loader in subtle ways.
1452 Directories are separated by the platform path separator (colons on unix). Example:
1453 .B /home/username/lib:/usr/local/mono/lib
1455 Relative paths are resolved based on the launch-time current directory.
1457 Alternative solutions to MONO_PATH include: installing libraries into
1458 the Global Assembly Cache (see gacutil(1)) or having the dependent
1459 libraries side-by-side with the main executable.
1461 For a complete description of recommended practices for application
1463 http://www.mono-project.com/docs/getting-started/application-deployment/
1466 Experimental RTC support in the statistical profiler: if the user has
1467 the permission, more accurate statistics are gathered. The MONO_RTC
1468 value must be restricted to what the Linux rtc allows: power of two
1469 from 64 to 8192 Hz. To enable higher frequencies like 4096 Hz, run as root:
1472 echo 4096 > /proc/sys/dev/rtc/max-user-freq
1479 MONO_RTC=4096 mono --profiler=default:stat program.exe
1483 \fBMONO_SHARED_DIR\fR
1484 If set its the directory where the ".wapi" handle state is stored.
1485 This is the directory where the Windows I/O Emulation layer stores its
1486 shared state data (files, events, mutexes, pipes). By default Mono
1487 will store the ".wapi" directory in the users's home directory.
1489 \fBMONO_SHARED_HOSTNAME\fR
1490 Uses the string value of this variable as a replacement for the host name when
1491 creating file names in the ".wapi" directory. This helps if the host name of
1492 your machine is likely to be changed when a mono application is running or if
1493 you have a .wapi directory shared among several different computers.
1495 Mono typically uses the hostname to create the files that are used to
1496 share state across multiple Mono processes. This is done to support
1497 home directories that might be shared over the network.
1499 \fBMONO_STRICT_IO_EMULATION\fR
1500 If set, extra checks are made during IO operations. Currently, this
1501 includes only advisory locks around file writes.
1504 The name of the theme to be used by Windows.Forms. Available themes today
1505 include "clearlooks", "nice" and "win32".
1507 The default is "win32".
1509 \fBMONO_TLS_SESSION_CACHE_TIMEOUT\fR
1510 The time, in seconds, that the SSL/TLS session cache will keep it's entry to
1511 avoid a new negotiation between the client and a server. Negotiation are very
1512 CPU intensive so an application-specific custom value may prove useful for
1513 small embedded systems.
1515 The default is 180 seconds.
1517 \fBMONO_THREADS_PER_CPU\fR
1518 The minimum number of threads in the general threadpool will be
1519 MONO_THREADS_PER_CPU * number of CPUs. The default value for this
1522 \fBMONO_XMLSERIALIZER_THS\fR
1523 Controls the threshold for the XmlSerializer to produce a custom
1524 serializer for a given class instead of using the Reflection-based
1525 interpreter. The possible values are `no' to disable the use of a
1526 custom serializer or a number to indicate when the XmlSerializer
1527 should start serializing. The default value is 50, which means that
1528 the a custom serializer will be produced on the 50th use.
1530 \fBMONO_X509_REVOCATION_MODE\fR
1531 Sets the revocation mode used when validating a X509 certificate chain (https,
1532 ftps, smtps...). The default is 'nocheck', which performs no revocation check
1533 at all. The other possible values are 'offline', which performs CRL check (not
1534 implemented yet) and 'online' which uses OCSP and CRL to verify the revocation
1535 status (not implemented yet).
1536 .SH ENVIRONMENT VARIABLES FOR DEBUGGING
1538 \fBMONO_ASPNET_NODELETE\fR
1539 If set to any value, temporary source files generated by ASP.NET support
1540 classes will not be removed. They will be kept in the user's temporary
1544 If set, enables some features of the runtime useful for debugging.
1545 This variable should contain a comma separated list of debugging options.
1546 Currently, the following options are supported:
1550 \fBalign-small-structs\fR
1551 Enables small structs alignment to 4/8 bytes.
1553 \fBarm-use-fallback-tls\fR
1554 When this option is set on ARM, a fallback TLS will be used instead
1555 of the default fast TLS.
1557 \fBbreak-on-unverified\fR
1558 If this variable is set, when the Mono VM runs into a verification
1559 problem, instead of throwing an exception it will break into the
1560 debugger. This is useful when debugging verifier problems
1563 This option can be used to get more detailed information from
1564 InvalidCast exceptions, it will provide information about the types
1567 \fBcheck-pinvoke-callconv\fR
1568 This option causes the runtime to check for calling convention
1569 mismatches when using pinvoke, i.e. mixing cdecl/stdcall. It only
1570 works on windows. If a mismatch is detected, an
1571 ExecutionEngineException is thrown.
1573 \fBcollect-pagefault-stats\fR
1574 Collects information about pagefaults. This is used internally to
1575 track the number of page faults produced to load metadata. To display
1576 this information you must use this option with "--stats" command line
1579 \fBdebug-domain-unload\fR
1580 When this option is set, the runtime will invalidate the domain memory
1581 pool instead of destroying it.
1583 \fBdont-free-domains\fR
1584 This is an Optimization for multi-AppDomain applications (most
1585 commonly ASP.NET applications). Due to internal limitations Mono,
1586 Mono by default does not use typed allocations on multi-appDomain
1587 applications as they could leak memory when a domain is unloaded.
1589 Although this is a fine default, for applications that use more than
1590 on AppDomain heavily (for example, ASP.NET applications) it is worth
1591 trading off the small leaks for the increased performance
1592 (additionally, since ASP.NET applications are not likely going to
1593 unload the application domains on production systems, it is worth
1594 using this feature).
1596 \fBdyn-runtime-invoke\fR
1597 Instructs the runtime to try to use a generic runtime-invoke wrapper
1598 instead of creating one invoke wrapper.
1600 \fBexplicit-null-checks\fR
1601 Makes the JIT generate an explicit NULL check on variable dereferences
1602 instead of depending on the operating system to raise a SIGSEGV or
1603 another form of trap event when an invalid memory location is
1607 Equivalent to setting the \fBMONO_XDEBUG\fR variable, this emits
1608 symbols into a shared library as the code is JITed that can be loaded
1609 into GDB to inspect symbols.
1611 \fBgen-seq-points\fR
1612 Automatically generates sequence points where the
1613 IL stack is empty. These are places where the debugger can set a
1616 \fBgen-compact-seq-points\fR
1617 This option generates sequence points data that maps native offsets to
1618 IL offsets. Sequence point data is used to display IL offset in
1619 stacktraces. Stacktraces with IL offsets can be symbolicated using
1620 mono-symbolicate tool.
1623 Captures the interrupt signal (Control-C) and displays a stack trace
1624 when pressed. Useful to find out where the program is executing at a
1625 given point. This only displays the stack trace of a single thread.
1628 Instructs the runtime to initialize the stack with
1629 some known values (0x2a on x86-64) at the start of a method to assist
1630 in debuggin the JIT engine.
1632 \fBkeep-delegates\fR
1633 This option will leak delegate trampolines that are no longer
1634 referenced as to present the user with more information about a
1635 delegate misuse. Basically a delegate instance might be created,
1636 passed to unmanaged code, and no references kept in managed code,
1637 which will garbage collect the code. With this option it is possible
1638 to track down the source of the problems.
1640 \fBno-gdb-backtrace\fR
1641 This option will disable the GDB backtrace emitted by the runtime
1642 after a SIGSEGV or SIGABRT in unmanaged code.
1644 \fBpartial-sharing\fR
1645 When this option is set, the runtime can share generated code between
1646 generic types effectively reducing the amount of code generated.
1648 \fBreverse-pinvoke-exceptions
1649 This option will cause mono to abort with a descriptive message when
1650 during stack unwinding after an exception it reaches a native stack
1651 frame. This happens when a managed delegate is passed to native code,
1652 and the managed delegate throws an exception. Mono will normally try
1653 to unwind the stack to the first (managed) exception handler, and it
1654 will skip any native stack frames in the process. This leads to
1655 undefined behaviour (since mono doesn't know how to process native
1656 frames), leaks, and possibly crashes too.
1658 \fBsingle-imm-size\fR
1659 This guarantees that each time managed code is compiled the same
1660 instructions and registers are used, regardless of the size of used
1663 \fBsoft-breakpoints\fR
1664 This option allows using single-steps and breakpoints in hardware
1665 where we cannot do it with signals.
1667 \fBsuspend-on-sigsegv\fR
1668 This option will suspend the program when a native SIGSEGV is received.
1669 This is useful for debugging crashes which do not happen under gdb,
1670 since a live process contains more information than a core file.
1672 \fBsuspend-on-exception\fR
1673 This option will suspend the program when an exception occurs.
1675 \fBsuspend-on-unhandled\fR
1676 This option will suspend the program when an unhadled exception occurs.
1680 \fBMONO_LOG_LEVEL\fR
1681 The logging level, possible values are `error', `critical', `warning',
1682 `message', `info' and `debug'. See the DEBUGGING section for more
1686 Controls the domain of the Mono runtime that logging will apply to.
1687 If set, the log mask is changed to the set value. Possible values are
1688 "asm" (assembly loader), "type", "dll" (native library loader), "gc"
1689 (garbage collector), "cfg" (config file loader), "aot" (precompiler),
1690 "security" (e.g. Moonlight CoreCLR support) and "all".
1691 The default value is "all". Changing the mask value allows you to display only
1692 messages for a certain component. You can use multiple masks by comma
1693 separating them. For example to see config file messages and assembly loader
1694 messages set you mask to "asm,cfg".
1697 Used for runtime tracing of method calls. The format of the comma separated
1706 disabled Trace output off upon start.
1709 You can toggle trace output on/off sending a SIGUSR2 signal to the program.
1711 \fBMONO_TRACE_LISTENER\fR
1712 If set, enables the System.Diagnostics.DefaultTraceListener, which will
1713 print the output of the System.Diagnostics Trace and Debug classes.
1714 It can be set to a filename, and to Console.Out or Console.Error to display
1715 output to standard output or standard error, respectively. If it's set to
1716 Console.Out or Console.Error you can append an optional prefix that will
1717 be used when writing messages like this: Console.Error:MyProgramName.
1718 See the System.Diagnostics.DefaultTraceListener documentation for more
1721 \fBMONO_WCF_TRACE\fR
1722 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.
1724 \fBMONO_XEXCEPTIONS\fR
1725 This throws an exception when a X11 error is encountered; by default a
1726 message is displayed but execution continues
1728 \fBMONO_XMLSERIALIZER_DEBUG\fR
1729 Set this value to 1 to prevent the serializer from removing the
1730 temporary files that are created for fast serialization; This might
1731 be useful when debugging.
1734 This is used in the System.Windows.Forms implementation when running
1735 with the X11 backend. This is used to debug problems in Windows.Forms
1736 as it forces all of the commands send to X11 server to be done
1737 synchronously. The default mode of operation is asynchronous which
1738 makes it hard to isolate the root of certain problems.
1741 When the the MONO_XDEBUG env var is set, debugging info for JITted
1742 code is emitted into a shared library, loadable into gdb. This enables,
1743 for example, to see managed frame names on gdb backtraces.
1745 \fBMONO_VERBOSE_METHOD\fR
1746 Enables the maximum JIT verbosity for the specified method. This is
1747 very helpfull to diagnose a miscompilation problems of a specific
1750 \fBMONO_VERBOSE_HWCAP\fR
1751 If set, makes the JIT output information about detected CPU features
1752 (such as SSE, CMOV, FCMOV, etc) to stdout.
1754 \fBMONO_CONSERVATIVE_HWCAP\fR
1755 If set, the JIT will not perform any hardware capability detection. This
1756 may be useful to pinpoint the cause of JIT issues. This is the default
1757 when Mono is built as an AOT cross compiler, so that the generated code
1758 will run on most hardware.
1760 If you want to use Valgrind, you will find the file `mono.supp'
1761 useful, it contains the suppressions for the GC which trigger
1762 incorrect warnings. Use it like this:
1764 valgrind --suppressions=mono.supp mono ...
1767 On some platforms, Mono can expose a set of DTrace probes (also known
1768 as user-land statically defined, USDT Probes).
1770 They are defined in the file `mono.d'.
1772 .B ves-init-begin, ves-init-end
1774 Begin and end of runtime initialization.
1776 .B method-compile-begin, method-compile-end
1778 Begin and end of method compilation.
1779 The probe arguments are class name, method name and signature,
1780 and in case of method-compile-end success or failure of compilation.
1784 Begin and end of Garbage Collection.
1786 To verify the availability of the probes, run:
1788 dtrace -P mono'$target' -l -c mono
1791 Mono's Ping implementation for detecting network reachability can
1792 create the ICMP packets itself without requiring the system ping
1793 command to do the work. If you want to enable this on Linux for
1794 non-root users, you need to give the Mono binary special permissions.
1796 As root, run this command:
1798 # setcap cap_net_raw=+ep /usr/bin/mono
1801 On Unix assemblies are loaded from the installation lib directory. If you set
1802 `prefix' to /usr, the assemblies will be located in /usr/lib. On
1803 Windows, the assemblies are loaded from the directory where mono and
1806 .B ~/.mono/aot-cache
1808 The directory for the ahead-of-time compiler demand creation
1809 assemblies are located.
1811 .B /etc/mono/config, ~/.mono/config
1813 Mono runtime configuration file. See the mono-config(5) manual page
1814 for more information.
1816 .B ~/.config/.mono/certs, /usr/share/.mono/certs
1818 Contains Mono certificate stores for users / machine. See the certmgr(1)
1819 manual page for more information on managing certificate stores and
1820 the mozroots(1) page for information on how to import the Mozilla root
1821 certificates into the Mono certificate store.
1823 .B ~/.mono/assemblies/ASSEMBLY/ASSEMBLY.config
1825 Files in this directory allow a user to customize the configuration
1826 for a given system assembly, the format is the one described in the
1827 mono-config(5) page.
1829 .B ~/.config/.mono/keypairs, /usr/share/.mono/keypairs
1831 Contains Mono cryptographic keypairs for users / machine. They can be
1832 accessed by using a CspParameters object with DSACryptoServiceProvider
1833 and RSACryptoServiceProvider classes.
1835 .B ~/.config/.isolatedstorage, ~/.local/share/.isolatedstorage, /usr/share/.isolatedstorage
1837 Contains Mono isolated storage for non-roaming users, roaming users and
1838 local machine. Isolated storage can be accessed using the classes from
1839 the System.IO.IsolatedStorage namespace.
1841 .B <assembly>.config
1843 Configuration information for individual assemblies is loaded by the
1844 runtime from side-by-side files with the .config files, see the
1845 http://www.mono-project.com/Config for more information.
1847 .B Web.config, web.config
1849 ASP.NET applications are configured through these files, the
1850 configuration is done on a per-directory basis. For more information
1851 on this subject see the http://www.mono-project.com/Config_system.web
1854 Mailing lists are listed at the
1855 http://www.mono-project.com/community/help/mailing-lists/
1857 http://www.mono-project.com
1860 certmgr(1), csharp(1), mcs(1), mdb(1), monocov(1), monodis(1),
1861 mono-config(5), mozroots(1), mprof-report(1), pdb2mdb(1), xsp(1), mod_mono(8).
1863 For more information on AOT:
1864 http://www.mono-project.com/docs/advanced/aot/
1866 For ASP.NET-related documentation, see the xsp(1) manual page
projects / mono.git / blob