[Discuss-gnuradio] forecast and general work function

[s . subrata105]

I am trying to create a block that has two input and one output. Its like a 
priority multiplexer; if input0 is empty then output = input1 else output = 
input0 ( input0 always has samples) its a stream based block. 
How do I declare the work function, because the number of samples needed from 
each input to produce noutput_items depends on whether input0 is empty. 
Any help in the general work function is also greatly appreciated.

Thanks