[bedevtalk] SendReply seems actually to succeed only the first time for me

[John Ashmun]

Hello.

After quite a long delay, I've resumed developing a little on my  
development BeBox.

Here's my scenario:  I have two teams, which can be considered a  
server and a client, intended to be run on the same system (the server  
is useful running alone, and the client provides a simple user  
interface for it).

The server spawns and starts a thread which does some calculations,  
while its main thread runs its message loop.

When the client is started, it sends a BMessage containing its  
be_app_messenger to the server.  The server's main thread caches that  
BMessenger.

When a button is clicked in the client's window, the client forwards  
the button's message to the server.  This causes the server to begin  
sending messages about its state to the client.  The client displays  
the state data in its window.

Here's my problem:  I don't want to flood the client with messages  
that cause the screen to be updated so often that the user would have  
no chance to read the data, but I do want frequent automatic updates  
until another button is clicked (causing the server to stop sending  
messages), so my protocol also requires the server to receive a reply  
from the client before it sends another message with its latest state  
data.  In the server, I used the flavor of SendMessage( msg, &reply )  
that waits for a reply to arrive, but what I found is that although  
the status returned by SendReply( ... ) in the client succeeds when it  
replies to each of the first two server state messages, the reply  
BMessage received by the server has a what value of B_NO_REPLY for the  
second reply.  Why is this?

(I've worked around this by calling the SendMessage( msg ) flavor that  
doesn't expect a reply in the server and setting a flag in there to  
skip sending its messages, and by sending the client's replies using  
SendMessage(  ) rather than SendReply( ), and in the server main  
thread's MessageReceived( ) function, clearing the flag when a reply  
has arrived from the client, but I'd like to know what wasn't working  
when I tried waiting for a reply message via SendReply( ).)

Regards,
John