[gtkmm] Glib::SignalIO

[Peter Gasper <pgasper designadvantage com>]

My application is reading information from the serial port. I first wrote a test 
program that ran from the command-line to do this. Then I set about incorporating it 
into my gtkmm app. It originally used the sigaction SIGIO signal to implement
asynchronous IO, which worked really well. However when I brought it into my app I had
problems with the line:
	sa.sa_handler = on_input_received;
Which previously was just a regular function, but now in my app is part of a class,
which causes the compiler warning: 
	"cannot convert 'void (Serial::*)(int)' to 'void (*)(int)' in assignment"
for the line:
	sa.sa_handler = &Serial::on_input_received;

Now maybe there is a code solution to this, but I don't know it. So I changed to using
Glib::SignalIO function, which one would expect to have the same functionality.
Therein lies the problem.

1. I had been using pause(), which pauses my function until the sigaction SIGIO signal
	is received, I cannot find a similar functionality for Glib::SignalIO.
2. Unlike the sigaction SIGIO (which calls only while input is available),
	the Glib::SignalIO repeatedly calls my slot until I return false, even if
	no more data is available. Because of this I return false so I don't get
	false signals. But this means I must reconnect the slot to the SignalIO
	which means I could potentially miss a signal for incoming data. Which means
	Glib::SignalIO acts more like an unreliable signal than a reliable signal 
	such as sigaction SIGIO.

>From the documentation it also appears that all Glib::SignalIO does is poll fd, which
I can do myself, but I was trying to avoid polling (which is more CPU intensive). 

Any ideas?