accessing rs232 using C/C++

[PESITdude]

Hi,
I wanted to know how to access hardware (like rs232, mouse, keyboard, usb) using a C/C++ program. I'm interested in writing a small program to transfer a text file from PC to a micro-controller (or any other device for that matter) connected via rs232! I'd be grateful if anyone can help me out...

Thanks in advance!