How can I do serial (``comm'') port I/O?
It's system-dependent. Under Unix, you typically open, read, and write a device
file in /dev, and use the facilities of the terminal driver to adjust its characteristics.Under
MS-DOS, you can use the predefined stream stdaux, or a special file like COM1, or
some primitive BIOS interrupts, or (if you require decent performance) any number
of interrupt-driven serial I/O packages. Several netters recommend the book C Programmer's
Guide to Serial Communications, by Joe Campbell.