dbus_connection_send_with_reply_and_block and unrelated messages

[Havoc Pennington]

Daniel P. Berrange wrote:
> 
> The way I dealt with this in Perl bindings is to have a pre-select/pre-poll
> hook, which runs the following:
> 
>     while(dbus_connection_dispatch(con) == DBUS_DISPATCH_DATA_REMAINS);
> 
> So once we get into the select/poll function we're sure there are no 
> outstanding messages to be dealt with. It seems to be working pretty
> effectively thus far.
> 

The basic intent is that anytime you have dbus read from the socket 
(which would include all blocking functions, and an explicit 
dbus_connection_read_write), you need to check the dispatch status prior 
to returning to poll/select.

So the above is one approach, you can also use get_dispatch_status() or 
the set_dispatch_status_func() as two ways to get the dispatch status 
without having to actually dispatch. The dispatch_status_func is called 
in all kinds of crazy contexts so I would be sure to only _queue_ 
dispatch in there, don't try to actually dispatch or the reentrancy will 
get dangerous.

Havoc