Re: mach_msg trouble

[Constantine Kousoulos]

Constantine Kousoulos wrote:
> ... 
>   port_err=mach_port_allocate(mach_task_self(),
> MACH_PORT_RIGHT_RECEIVE, &name);
>   if (port_err!=KERN_SUCCESS)
>     error(1, port_err, "cannot allocate port, %d", port_err);
>
>   msg_err=mach_msg(&msg_body, MACH_RCV_MSG, 0, sizeof(msg_body),
>             XXX,
>             MACH_MSG_TIMEOUT_NONE,
>             MACH_PORT_NULL);
>   if (msg_err!=MACH_MSG_SUCCESS)
>     error(1, msg_err, "error receiving message, %d", msg_err);
>
> I don't know what to put instead of XXX to make this task
> reveive messages at the allocated port.

I bypassed the previous problem using

mach_port_t rcv = mach_reply_port();
msg_err=mach_msg(&header, MACH_RCV_MSG, 0, sizeof(header),
                        rcv,
                        MACH_MSG_TIMEOUT_NONE,
                        MACH_PORT_NULL);

> Secondly, how can a client discover this server's port in order to send 
> something?

Let me explain a bit more and correct me if i am wrong. In order 
for two threads to communicate via mach_msg(), those two threads 
must belong to the same task. In order for a client program to 
communicate with an entirely different server program, mig or 
sockets are needed. When mig is used, how can i bind my server 
program to a specific port to listen for messages?


Thanks in any case,
Constantine