01-05-2008
Processes Communication Only with flags!
hello everybody and a happy new year!
i am trying the client-server model...i have no problem with sockets etc...
especially for server:there is a father who is listening for TCP connections from clients,the later send commands which parent shares to his children.
then children execute commands and send the results to each client through UDP connectionless communication...
my problem is that father,who read commands from clients,read them to a pipe and children processes reads them from there...the first free child must read command from a pipe to which parent is writing.
unfortunately we are not supposed to use thread-mutex-shared memory-
we only can use a flag which allows a child to read o command (message from father each time) and i don't know how to use that flag...
i must have a flag to a pipe and the first free process takes the flag read the message and puts back the flag...how can i do something like that?
i see that there is a need for such a flag because when i have one pipe
and e.g.:5 children let the parent write a command to the pipe
then we need only one child to read the whole command...which won't happen without a flag preventing other children from reading until the above child reads the whole command and put back the flag...
thanks a lot!
note:we have NUMCHILDREN children given as an argument.
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rpc(n) Tnm Tcl Extension rpc(n)
__________________________________________________________________________________________________________________________________________________
NAME
rpc - A simple RPC protocol for Tcl applications.
_________________________________________________________________
DESCRIPTION
RPC COMMAND
rpc server port
Set up an RPC server listening an port port. This command returns a rpc handle that be used to register Tcl procs that will be
exported by a trivial RPC protocol on top of TCP. This RPC mechanism allows us to write cooperating scripts without worrying much
about the communication protocol.
rpc client host port
Connect to the RPC server running on host with port port. The returned client handle can be used to invoke an exported proc on the
server host.
rpc delete handle
Delete a server or a client RPC handle. All connections associated with the handle will be closed.
rpc register rpchandle proc
Export proc as an RPC callable proc using the server handle rpchandle. Only registered procs can be called by RPC clients.
rpc unregister rpchandle proc
Remove proc from the list of exported procs on server handle rpchandle.
rpc info [rpchandle]
Calling rpc info without any arguments returns a list of all rpc handles that have been created using the rpc server and rpc client
command. Info about a specific rpc file handle rpchandle is returned by using the optional argument. The result is a list contain-
ing the tcp file handle used for the communication and the list of registered commands for a rpc handle and a list of all files that
represent connections to an rpc server. This list is empty if rpchandle belongs to a rpc client.
rpc# [-async] proc arg1 arg2 ...
To invoke a remote procedure proc, use the same syntax as used with a local invocation preceeded by a client rpchandle. The result
of the remote procedure call will be returned or an error if the underlying communication channel signals errors. The -async options
can be used to invoke proc without waiting for it to complete. The async option will never return a result.
SEE ALSO
scotty(1), Tcl(n)
AUTHORS
Juergen Schoenwaelder <schoenw@cs.utwente.nl>
Tnm rpc(n)