Hi, I have been working on a small library that has become reasonably useful and possibly of interest to someone else. It's also become fairly large. I am quite interested in this library getting "boosted" but even given that there is substance to the library its scope is a bit of a problem; its quite large. It was started as a project with requirements very similar to those associated with the ActiveObject pattern; http://citeseer.nj.nec.com/lavender96active.html (reference from J. Garland) and takes many cues from the concepts and primitives found in SDL; http://www.sdl-forum.org/ Its possible to characterize this library as the basic building blocks for clean, robust multi-threading <ahem>. It could also be characterized as a subset of TAO, i.e. CORBA. While its a very small subset <sheepish grin>, maybe these comments gives scale to the scope issue. A breakdown of the incidental technologies tackled by this library follows; * multi-threading building block classes * network representation of structured data (variants) * saving and loading of network data (persistence) * interactive machines (inter-thread messaging) * stateless and stateful machine representation * code generation of network data and machine skeletons * message forwarding (distributed messaging) * transparent remote machines (proxies for inter-process messaging) * support for multiple encodings, e.g. binary, text, XML... To flesh this list out into something less opaque, a set of file fragments follows. These are the result of applying the library to the test case pushed around in the recent thread "Simple Active Object". They are necessarily abbreviated; // --------------------------------- // db_server.tms (the schema) // record configuration { // Persistent portion of the db_server string data_source integer maximum_workers integer maximum_clients } record open {} // Messages between the server and its clients record close {} record select { string sql_statement } record busy {} state INTIAL, // Pre-defined READY, // Normal operation OVERLOADED, // All workers busy OUT_OF_SERVICE // Something went wrong // Define the messages expected in the // different states transition INITIAL void // Standard startup transition READY open, // Another client connecting close, // Client closing configuration, // Reconfiguration select // An SQL select statement .. // --------------------------------- // db_server.h (auto-generated header) // .. #define db_server_configuration_hash 0x03493ac9 #define db_server_open_hash 0x7a6ffa00 #define db_server_close_hash 0x1093ac66 #define db_server_select_hash 0x004410ac #define db_server_busy_hash 0x74529711 struct typed03493ac9 { .. string &data_source; long &maximum_workers; long &maximum_clients; .. }; struct db_server { .. enum { INITIAL, READY, OVERLOADED, OUT_OF_SERVICE }; typedef typed03493ac9 configuration; typedef typed7a6ffa00 open; typedef typed1093ac66 close; typedef typed004410ac select; typedef typed74529711 busy; virtual int transition( typed_state<INITIAL> ) = 0; // void message virtual int transition( typed_state<READY>, typed_bind<open> & ) = 0; virtual int transition( typed_state<READY>, typed_bind<close> & ) = 0; virtual int transition( typed_state<READY>, typed_bind<configuration> & ) = 0; virtual int transition( typed_state<READY>, typed_bind<select> & ) = 0; int machine( typed_word & ); // The auto-generated switch statements .. }; .. // --------------------------------- // my_server.cpp (application declaration of db_server) // #include "db_server.h" class my_server : public state_machine<db_server> { typed_memory_folder home; db_server configuration; address_group client; virtual int transition( typed_state<INITIAL> ); virtual int transition( typed_state<READY>, typed_bind<open> & ); .. }; // my_server.cpp (application definition of db_server) // my_server::my_server() : home( "configuration\\my_server" ) { try // Persistence { load( home, configuration ); // Recover previous image } catch( ... ) { // Not found. Set factory defaults configuration.data_source = ""; configuration.maximum_workers = 4; configuration.maximum_clients = 100; save( home, configuration ); } } int my_server::transition( typed_state<INITIAL> ) { if( data_source.empty() ) { return OUT_OF_SERVICE; } if( ... ) // Attempt to connect to RDBMS { return READY; } return OUT_OF_SERVICE; } int my_server::transition( typed_state<READY>, typed_bind<open> &s ) { client.insert( sender() ); reply( configuration ); } .. int my_server::transition( typed_state<READY>, typed_bind<select> &s ) { if( ... ) // Find an idle worker { // Submit request to worker .. return READY; } reply( busy() ); return READY; } Hopefully these fragments have been enough to sketch out the intent of the library and where it currently is "at". As a bunch of materials, it is a .lib, headers and a .exe (the schema parser+generator) There are (serious) pretentions to platform independence but current materials are for Windows. I am very happy to work towards a boosted version of a subset of this work cos basically it seems too large to be a prospect otherwise. This subset would be in the area of mutli-threading building block classes, i.e. an "alternate threading model". However, after the recent exchange of related and interesting messages, I felt compelled to "come clean" with some background. So, to Matthew and Mark. Are you interested in dicsussing the possible implementation of; * simple active objects (completion of current alternate threading model) * simple reactive objects (completion of current with two-way calling of methods) * something else? Cheers, Scott