What is a file descriptor in Linux? What are standard files? What are their descriptors?
时间: 2024-05-20 16:16:33 浏览: 13
A file descriptor is a unique identifier that the operating system uses to refer to an open file. It is an integer value that is used by programs to read, write, and manipulate files. In Linux, file descriptors are used to represent all types of input/output resources, including files, pipes, sockets, and devices.
Standard files are a set of predefined files that are automatically opened by every process when it starts running. These files are used for input and output operations and provide a standard way for programs to interact with the operating system. There are three standard files:
1. Standard input (stdin): This file is used for input operations and is usually connected to the keyboard or a file.
2. Standard output (stdout): This file is used for output operations and is usually connected to the screen or a file.
3. Standard error (stderr): This file is used for error messages and is also usually connected to the screen or a file.
The descriptors for the standard files are:
1. stdin: 0
2. stdout: 1
3. stderr: 2
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