Signals & threads - low level C API [Newbie question]

Havoc Pennington hp at
Fri Jan 26 11:44:17 PST 2007

Krishna R wrote:
> Do i still need the main loop you are talking about in the above simple 
> scenario?

The problem is that there's a lock on the socket. When 
read_write_dispatch() blocks, it will hold this lock. That means 
dbus_connection_flush() can't acquire it in order to flush.

You can imagine various libdbus fixes to make it smarter about this 
situation, but if you don't want to hack on libdbus you probably have to 
  only call read_write_dispatch() when you know it won't block, which is 
normally done with a main loop as Thiago suggests. As a hack you could 
also just call dbus_connection_get_socket() and poll()/select() on it 
manually in a simple loop.

An even worse hack would be to try and wake up the poll by creating an 
EINTR (raise some bogus signal), but I don't know if that will work and 
it probably isn't that portable across unix flavors if it does.

Another bad hack would be to put a short timeout on the 
read_write_dispatch so it never blocks too long.


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