Operating Systems Question Bank with Answers 16

What is a file descriptor? What are the file descriptors in Unix OS for stdin, stdout, and stderr, respectively?

Question:

What is a file descriptor? What are the file descriptors in Unix OS for stdin, stdout, and stderr, respectively?

Answer:

A file descriptor is a handle represented by an integer that identifies an open file, pipe, or socket that belongs to a process. The kernel maintains a table of file descriptors that are used to reference open files and input/output (I/O) streams. 

In Unix, 0, 1, and 2 are reserved for standard input (stdin), standard output (stdout), and standard error (stderr), respectively.

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