Embedding Mono
	The Mono runtime can be embedded into C and C++
	applications.   Your C/C++ code can invoke managed code
	running in the Mono/.NET world and you can also surface your
	internal application APIs to Mono and .NET.
	
For an overview of how to embed Mono into your application
	and the strategies that you can use to embed Mono, check the
	Mono
	website's 
Embedding
	Mono page.
	
This page is the companion API reference for the above guide.
	
	
The simplest way of embedding Mono is illustrated here:
int main (int argc, char *argv)
{
	/*
	 * Load the default Mono configuration file, this is needed
	 * if you are planning on using the dllmaps defined on the
	 * system configuration
	 */
	mono_config_parse (NULL);
	/*
	 * mono_jit_init() creates a domain: each assembly is
	 * loaded and run in a MonoDomain.
	 */
	MonoDomain *domain = mono_jit_init ("startup.exe");
	/*
	 * Optionally, add an internal call that your startup.exe
	 * code can call, this will bridge startup.exe to Mono
	 */
	mono_add_internal_call ("Sample::GetMessage", getMessage);
	/*
	 * Open the executable, and run the Main method declared
	 * in the executable
	 */
	MonoAssembly *assembly = mono_domain_assembly_open (domain, "startup.exe");
	if (!assembly)
		exit (2);
	/*
	 * mono_jit_exec() will run the Main() method in the assembly.
	 * The return value needs to be looked up from
	 * System.Environment.ExitCode.
	 */
	mono_jit_exec (domain, assembly, argc, argv);
}
/* The C# signature for this method is: string GetMessage () in class Sample */
MonoString*
getMessage ()
{
	return mono_string_new (mono_domain_get (), "Hello, world");
}
    mono_jit_init
    
        
        
            
            Syntax
            MonoDomain* 
mono_jit_init (const char *file)
            
         
     
  
    mono_jit_parse_options
    
        
        
            
            Syntax
            void
mono_jit_parse_options (int argc, char * argv[])
            
             Description
             
 Process the command line options in 
argv as done by the runtime executable.
 This should be called before 
mono_jit_init.
 
         
     
  
    mono_jit_exec
    
        
        
            
            Syntax
            int 
mono_jit_exec (MonoDomain *domain, MonoAssembly *assembly, int argc, char *argv[])
            
            Parameters
            | assembly | reference to an assembly | 
| argc | argument count | 
| argv | argument vector | 
             Description
             
 Start execution of a program.
         
     
  
    mono_set_dirs
    
        
        
            
            Syntax
            void
mono_set_dirs (const char *assembly_dir, const char *config_dir)
            
            Parameters
            | assembly_dir | the base directory for assemblies | 
| config_dir | the base directory for configuration files | 
             Description
             
 This routine is used internally and by developers embedding
 the runtime into their own applications.
 There are a number of cases to consider: Mono as a system-installed
 package that is available on the location preconfigured or Mono in
 a relocated location.
 If you are using a system-installed Mono, you can pass 
NULL
 to both parameters.  If you are not, you should compute both
 directory values and call this routine.
 The values for a given PREFIX are:
    assembly_dir: PREFIX/lib
    config_dir:   PREFIX/etc
 Notice that embedders that use Mono in a relocated way must
 compute the location at runtime, as they will be in control
 of where Mono is installed.
 
         
     
  
    mono_parse_default_optimizations
    
        
        
            
            Syntax
            int
mono_parse_default_optimizations (const char* p)
            
         
     
  
    mono_runtime_set_main_args
    
        
        
            
            Syntax
            int
mono_runtime_set_main_args (int argc, char* argv[])
            
            Parameters
            | argc | number of arguments from the command line | 
| argv | array of strings from the command line | 
             Description
             
 Set the command line arguments from an embedding application that doesn't otherwise call
 mono_runtime_run_main.
         
     
  
    mono_jit_cleanup
    
        
        
            
            Syntax
            void        
mono_jit_cleanup (MonoDomain *domain)
            
         
     
  
    mono_jit_set_trace_options
    
        
        
            
            Syntax
            gboolean
mono_jit_set_trace_options (const char* options)
            
            Parameters
            | options | string representing the trace options | 
             Return value
             	 TRUE if the options were parsed and set correctly, FALSE otherwise.
             Description
             
 Set the options of the tracing engine. This function can be called before initializing
 the mono runtime. See the --trace mono(1) manpage for the options format.
 
     
Internal Calls
	The Mono runtime provides two mechanisms to expose C code
	to the CIL universe: internal calls and native C
	code. Internal calls are tightly integrated with the runtime,
	and have the least overhead, as they use the same data types
	that the runtime uses.
	
The other option is to use the Platform Invoke (P/Invoke)
	to call C code from the CIL universe, using the standard
	
P/Invoke
	mechanisms.
	
To register an internal call, use this call you use the
	
mono_add_internal_call
	routine.
  
    mono_add_internal_call
    
        
        
            
            Syntax
            void
mono_add_internal_call (const char *name, gconstpointer method)
            
            Parameters
            | name | method specification to surface to the managed world | 
| method | pointer to a C method to invoke when the method is called | 
             Description
             
 This method surfaces the C function pointed by 
method as a method
 that has been surfaced in managed code with the method specified in
 
name as an internal call.
 Internal calls are surfaced to all app domains loaded and they are
 accessibly by a type with the specified name.
 You must provide a fully qualified type name, that is namespaces
 and type name, followed by a colon and the method name, with an
 optional signature to bind.
 For example, the following are all valid declarations:
 MyApp.Services.ScriptService:Accelerate
 MyApp.Services.ScriptService:Slowdown(int,bool)
 You use method parameters in cases where there might be more than
 one surface method to managed code.  That way you can register different
 internal calls for different method overloads.
 The internal calls are invoked with no marshalling.   This means that .NET
 types like 
System.String are exposed as 
MonoString* parameters.   This is
 different than the way that strings are surfaced in P/Invoke.
 For more information on how the parameters are marshalled, see the
 
Mono Embedding
 page.
 See the 
Method Description
 reference for more information on the format of method descriptions.
 
         
     
P/Invoke with embedded applications
	Unlike internal calls, Platform/Invoke is easier to use and
	more portable.  It allows you to share code with Windows and
	.NET that have a different setup for internal calls to their
	own runtime.
	
Usually P/Invoke declarations reference external libraries
	like:
	
	[DllImport ("opengl")]
	void glBegin (GLEnum mode)
	
	Mono extends P/Invoke to support looking up symbols not in
	an external library, but looking up those symbols into the
	same address space as your program, to do this, use the
	special library name "__Internal".   This will direct Mono to
	lookup the method in your own process.
	
There are situations where the host operating system does
	not support looking up symbols on the process address space.
	For situations like this you can use
	the 
mono_dl_register_library. 
 
	
Data Marshalling
	Managed objects are represented as 
MonoObject*
	types.  Those objects that the runtime consumes directly have
	more specific C definitions (for example strings are of type
	
MonoString *, delegates are of type
	
MonoDelegate* but they are still 
MonoObject
	*s).
	
As of Mono 1.2.x types defined in mscorlib.dll do not have
	their fields reordered in any way.   But other libraries might
	have their fields reordered.   In these cases, Managed
	structures and objects have the same layout in the C# code as
	they do in the unmanaged world.
	
Structures defined outside corlib must have a specific
	StructLayout definition, and have it set as sequential if you
	plan on accessing these fields directly from C code.
	
Important Internal calls do not provide support for
	marshalling structures.  This means that any API calls that
	take a structure (excluding the system types like int32,
	int64, etc) must be passed as a pointer, in C# this means
	passing the value as a "ref" or "out" parameter.
Mono Runtime Configuration
	Certain features of the Mono runtime, like DLL mapping, are
	available through a configuration file that is loaded at
	runtime.   The default Mono implementation loads the
	configuration file from 
$sysconfig/mono/config
	(typically this is 
/etc/mono/config).
	
See the 
mono-config(5) man page for more details
	on what goes in this file.
	
The following APIs expose this functionality:
	
    mono_config_cleanup
    
        
        
            
            Syntax
            void
mono_config_cleanup (void)
            
         
     
  
    mono_config_is_server_mode
    
        
        
            
            Syntax
            mono_bool
mono_config_is_server_mode (void)
            
         
     
  
    mono_config_parse
    
        
        
            
            Syntax
            void
mono_config_parse (const char *filename)
            
            Parameters
            | filename | the filename to load the configuration variables from. | 
             Description
             
 Pass a NULL filename to parse the default config files
 (or the file in the MONO_CONFIG env var).
         
     
  
    mono_config_parse_memory
    
        
        
            
            Syntax
            void
mono_config_parse_memory (const char *buffer)
            
            Parameters
            | buffer | a pointer to an string XML representation of the configuration | 
             Description
             
 Parses the configuration from a buffer
         
     
  
    mono_config_set_server_mode
    
        
        
            
            Syntax
            void
mono_config_set_server_mode (mono_bool server_mode)
            
         
     
  
    mono_config_string_for_assembly_file
    
        
        
            
            Syntax
            const char *
mono_config_string_for_assembly_file (const char *filename)
            
         
     
  
    mono_get_config_dir
    
        
        
            
            Syntax
            const char* 
mono_get_config_dir (void)
            
         
     
  
    mono_get_machine_config
    
        
        
            
            Syntax
            const char *
mono_get_machine_config (void)
            
         
     
  
    mono_register_machine_config
    
        
        
            
            Syntax
            void
mono_register_machine_config (const char *config_xml)
            
         
     
  
    mono_set_config_dir
    
        
        
            
            Syntax
            void
mono_set_config_dir (const char *dir)
            
             Description
             
 Invoked during startup
         
     
Advanced Execution Setups
	These are not recommended ways of initializing Mono, they
	are done internally by mono_jit_init, but are here to explain
	what happens internally.
	
  
    mono_runtime_exec_managed_code
    
        
        
            
            Syntax
            void
mono_runtime_exec_managed_code (MonoDomain *domain,
				MonoMainThreadFunc main_func,
				gpointer main_args)
            
            Parameters
            | domain | Application domain | 
| main_func | function to invoke from the execution thread | 
| main_args | parameter to the main_func | 
             Description
             
 Launch a new thread to execute a function
 main_func is called back from the thread with main_args as the
 parameter.  The callback function is expected to start 
Main
 eventually.  This function then waits for all managed threads to
 finish.
 It is not necessary anymore to execute managed code in a subthread,
 so this function should not be used anymore by default: just
 execute the code and then call mono_thread_manage().
 
     
  
    mono_runtime_exec_main
    
        
        
            
            Syntax
            mono_runtime_exec_main
            
         
     
  
    mono_init
    
        
        
            
            Syntax
            MonoDomain*
mono_init (const char *domain_name)
            
             Return value
             	 the initial domain.
             Description
             
 Creates the initial application domain and initializes the mono_defaults
 structure.
 This function is guaranteed to not run any IL code.
 The runtime is initialized using the default runtime version.
 
         
     
  
    mono_init_from_assembly
    
        
        
            
            Syntax
            MonoDomain*
mono_init_from_assembly (const char *domain_name, const char *filename)
            
            Parameters
            | domain_name | name to give to the initial domain | 
| filename | filename to load on startup | 
             Return value
             	 the initial domain.
             Description
             
 Used by the runtime, users should use mono_jit_init instead.
 Creates the initial application domain and initializes the mono_defaults
 structure.
 This function is guaranteed to not run any IL code.
 The runtime is initialized using the runtime version required by the
 provided executable. The version is determined by looking at the exe 
 configuration file and the version PE field)
 
         
     
  
    mono_init_version
    
        
        
            
            Syntax
            MonoDomain*
mono_init_version (const char *domain_name, const char *version)
            
             Return value
             	 the initial domain.
             Description
             
 Used by the runtime, users should use 
mono_jit_init instead.
 Creates the initial application domain and initializes the 
mono_defaults
 structure.
 This function is guaranteed to not run any IL code.
 The runtime is initialized using the provided rutime version.
 
         
     
  
    mono_jit_exec
    
        
        
            
            Syntax
            int 
mono_jit_exec (MonoDomain *domain, MonoAssembly *assembly, int argc, char *argv[])
            
            Parameters
            | assembly | reference to an assembly | 
| argc | argument count | 
| argv | argument vector | 
             Description
             
 Start execution of a program.
         
     
  
    mono_jit_set_aot_mode
    
        
        
            
            Syntax
            void
mono_jit_set_aot_mode (MonoAotMode mode)
            
         
     
  
    mono_set_break_policy
    
        
        
            
            Syntax
            void
mono_set_break_policy (MonoBreakPolicyFunc policy_callback)
            
            Parameters
            | policy_callback | the new callback function | 
             Description
             
 Allow embedders to decide whether to actually obey breakpoint instructions
 (both break IL instructions and 
Debugger.Break method calls), for example
 to not allow an app to be aborted by a perfectly valid IL opcode when executing
 untrusted or semi-trusted code.
 policy_callback will be called every time a break point instruction needs to
 be inserted with the method argument being the method that calls 
Debugger.Break
 or has the IL 
break instruction. The callback should return 
MONO_BREAK_POLICY_NEVER
 if it wants the breakpoint to not be effective in the given method.
 
MONO_BREAK_POLICY_ALWAYS is the default.
 
         
     
  
    mono_get_runtime_build_info
    
        
        
            
            Syntax
            char*
mono_get_runtime_build_info (void)
            
             Return value
             	 the runtime version + build date in string format.
             Description
             
 The returned string is owned by the caller. The returned string
 format is VERSION (FULL_VERSION BUILD_DATE) and build date is optional.
         
     
Signal Chaining
  
    mono_set_signal_chaining
    
        
        
            
            Syntax
            void
mono_set_signal_chaining (gboolean chain_signals)
            
             Description
             
 Enable/disable signal chaining. This should be called before 
mono_jit_init.
 If signal chaining is enabled, the runtime saves the original signal handlers before
 installing its own handlers, and calls the original ones in the following cases:
 - a 
SIGSEGV / 
SIGABRT signal received while executing native (i.e. not JITted) code.
 - 
SIGPROF
 - 
SIGFPE
 - 
SIGQUIT
 - 
SIGUSR2
 Signal chaining only works on POSIX platforms.