how to pass parameters between connected blocks

Hi, I'm using Simulink to generate C code for models. I build my own specific blocks using inlined S-function. But I wonder how to pass paramenters between connected blocks? That is to say, I want to know how to implement the function in my blocks that is when the inport of A connects to the outport of B. how to let block A knows the value of specific parameter of block B ? Could you give me some clue or examples? Thanks