11 Input/Output Overview
NOTE:
stream-based IO
NOTE:
file-descriptor-based-IO
5、Sockets
6、Low-Level Terminal Interface
11.1 Input/Output Concepts
Before you can read or write the contents of a file, you must establish a connection or communications channel to the file. This process is called opening the file. You can open a file for reading, writing, or both.
NOTE:
connection to file
The connection to an open file is represented either as a stream or as a file descriptor.