Multithreading
with Netbula RPC For Win32
Netbula RPC for Win32
supports multithreading, this document describe the procedure to build
multithreaded (MT) RPC server and clients.
MT Server
There are two methods
to create MT servers: thread on connect and thread on call.
Thread on connect
By calling pw_set_mt_on_connect(1)
(with argument being 1) before svc{proto}_create(), the newly created
service becomes a MT server.
- UDP service
The UDP service will run in a separate thread of itself
- TCP service
A new dedicated thread will be created for each client upon connection
to the server, the thread exits when the client close the connection
with the server.
One easy way to enable
this feature is define to RPC_MT_CONNECT macro in the .x file.
Thread on call
The option will cause
the server to create a new thread to handle an incoming RPC call, this
option is applied to individual procedures.
- ONC RPC
Enable this option by setting the mt_on_call field of the callInfo
structure to PWRPC_ONC_MT defined in powerrpc.h.
- PowerRPC
Enable this option by setting the mt_on_call field of the callInfo
structure to POWERRPC_THREADING defined in powerrpc.h.
MT Client
For ONC RPC, the return
result from server is stored in a static variable, to make this variable
thread local, define the PWRPC_MT macro. One way to do this is
to add a line
%define PWRPC_MT
in the *.x file.
A better way for programming
multi-threaded client is to use the two argument form of the RPC call.
Instead of using return value, one can pass in a pointer, which is used
to hold the return value. To use the two argument form you must define
the RPC_RETURN_ARG macro in the header. See
the MSG sample client program.
How to use
fix port for an RPC service and how to by-pass portmapper registration
To use fixed port
number for an RPC server is very easy. You just need to define the macros
{RPC_VERSION}_tcp_server_port
{RPC_VERSION}_udp_server_port
with the port numbers you want. For example, if you add
the following line to the msg.x file, the msg TCP server will use port
5555:
%#define MSGSERV_V1_tcp_server_port 5555
the UDP server will still use randomly assigned port
number.
To by-pass registration with portmapper, simply define
the following macros:
{RPC_VERSION}_tcp_no_pmap
{RPC_VERSION}_udp_no_pmap
For example,
#define MSGSERV_V1_tcp_no_pmap 1
will make the server skip portmapper registration for
the TCP part of the server.
How to use
TCP protocol to query the portmapper
When an RPC client connects to the server the first time, it needs
to find out the port number of the RPC server through the portmapper.
By default, the protocol for contacting the portmapper is UDP, which
may present some problems for certains situations. To use TCP protocol
for portmapper query, simply call the following function before the
clnt_create() calls.
pmap_set_use_tcp(1);
