mono-api-embedding.html
   
Embedding Mono
	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
    Prototype: mono_jit_init
  
 
    mono_jit_exec
    int 
mono_jit_exec (MonoDomain *domain, MonoAssembly *assembly, int argc, char *argv[])
Parameters
assembly: reference to an assemblyargc: argument countargv: argument vector
Remarks
	 
	 Start execution of a program.
  
 
    mono_set_dirs
    void
mono_set_dirs (const char *assembly_dir, const char *config_dir)
Parameters
assembly_dir: the base directory for assembliesconfig_dir: the base directory for configuration files
Remarks
	 
	 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_main
    int
mono_main (int argc, char* argv[])
Parameters
argc: number of arguments in the argv arrayargv: array of strings containing the startup arguments
Remarks
	 
	 Launches the Mono JIT engine and parses all the command line options
	 in the same way that the mono command line VM would.
  
 
    mono_parse_default_optimizations
    Prototype: mono_parse_default_optimizations
  
 
    mono_jit_cleanup
    Prototype: mono_jit_cleanup
  
 
    mono_set_defaults
    Prototype: mono_set_defaults
 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
    Prototype: mono_add_internal_call
 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_parse
    void
mono_config_parse (const char *filename)
Parameters
filename: the filename to load the configuration variables from.
Remarks
	 
	 Pass a NULL filename to parse the default config files
	 (or the file in the MONO_CONFIG env var).
  
 
    mono_config_parse_memory
    void
mono_config_parse_memory (const char *buffer)
Parameters
buffer: a pointer to an string XML representation of the configuration
Remarks
	 
	 Parses the configuration from a buffer
  
 
    mono_get_config_dir
    Prototype: mono_get_config_dir
 Function Pointers
	To wrap a function pointer into something that the Mono
	runtime can consume, you should use the mono_create_ftnptr.
	This is only important if you plan on running on the IA64
	architecture.   Otherwise you can just use the function
	pointer address.
	
 
 
    mono_create_ftnptr
    Prototype: mono_create_ftnptr
 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
    void
mono_runtime_exec_managed_code (MonoDomain *domain,
				MonoMainThreadFunc main_func,
				gpointer main_args)
Parameters
domain: Application domainmain_func: function to invoke from the execution threadmain_args: parameter to the main_func
Remarks
	 
	 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 necesseray 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
    Prototype: mono_runtime_exec_main
  
 
    mono_init_from_assembly
    MonoDomain*
mono_init_from_assembly (const char *domain_name, const char *filename)
Parameters
domain_name: name to give to the initial domainfilename: filename to load on startup
Returns
	  the initial domain.
Remarks
	 
	 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
    MonoDomain*
mono_init (const char *domain_name)
Returns
	  the initial domain.
Remarks
	 
	 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.