File Descriptor

File descriptors can refer to many kinds of object:

• terminal (keyboard / display)
• files on disk
• network connections
• devices, e.g. sound card, camera
• (but not threads or processes; use pid_t, tid_t)

These objects mostly support read() and write(), and some support additional operations:

• seek(): seek within a file; i.e. when dealing with audio or video
• ioctl(): for any other operation that doesn’t fit in these operations Could infer this is dynamically typed.