30 Input/output library [input.output]

30.10 File systems [filesystems]

30.10.1 General [fs.general]

This subclause describes operations on file systems and their components, such as paths, regular files, and directories.
A file system is a collection of files and their attributes.
A file is an object within a file system that holds user or system data.
Files can be written to, or read from, or both.
A file has certain attributes, including type.
File types include regular files and directories.
Other types of files, such as symbolic links, may be supported by the implementation.
A directory is a file within a file system that acts as a container of directory entries that contain information about other files, possibly including other directory files.
The parent directory of a directory is the directory that both contains a directory entry for the given directory and is represented by the filename dot-dot in the given directory.
The parent directory of other types of files is a directory containing a directory entry for the file under discussion.
A link is an object that associates a filename with a file.
Several links can associate names with the same file.
A hard link is a link to an existing file.
Some file systems support multiple hard links to a file.
If the last hard link to a file is removed, the file itself is removed.
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A hard link can be thought of as a shared-ownership smart pointer to a file.
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A symbolic link is a type of file with the property that when the file is encountered during pathname resolution ([fs.class.path]), a string stored by the file is used to modify the pathname resolution.
[Note
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Symbolic links are often called symlinks.
A symbolic link can be thought of as a raw pointer to a file.
If the file pointed to does not exist, the symbolic link is said to be a “dangling” symbolic link.
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