OpenDevice (C help needed please!)

[golem]

I'm learning how to program the serial device but finding it difficult to fathom the RKM examples.
e.g. return = OpenDevice(serial.device,0,(struct IoRequest *)IORequest, flags)

What I don't understand about that is what the (struct IORequest *) part does.
I understand you pass a pointer to an IORequest structure to the OpenDevice call but the above C declaration I no understand! I'm much more comfortable with 68k asm but figure it's time I learnt to do things properly!

Thanks

[golem]

Yes I keep reading your reply and its starting to make sense!

Thanks Chris

[golem]

Thanks Cymric - I thought it had something to do with casting.
I have got Kernigan and Ritchie and keep meaning to read it cover to cover but I'm a book dipper and keep trying to fly before I can walk! Same goes for the full set of ROM Kernel Manuals I have at last got hold of.
I think I need to work through K & R compiling the examples as I go and bite the bullet!