Introduction
The intended audience for this document are application programmers and providers of init-systems for managing features of installations of the GNU/Linux operating system and POSIX-compliant operating systems in general, who are concerned with per-user temporary file management based on the XDG Base Directory Specification, [XDG].
Many applications that follow XDG guidelines and specifications expect a directory with a location specified by environment variable XDG_RUNTIME_DIR. This directory – in the following called „rundir“ – stores files that serve purposes of process communication and synchronization; it is comparable to the directory /run, but on a per-user basis, with ownership and permissions set up so that every user of a system can have such a directory, protected from access by other users.
The existence of such a directory, requirements to this directory, management of the directory’s lifecycle and its denomination by the content of a user’s XDG_RUNTIME_DIR environment variable are mandated by [XDG].
