- xdg-runtime-dir #!key (set-environment? #t)procedure
Return the value of the XDG_RUNTIME_DIR environment variable if it is set and is not empty. Otherwise return #f.
By default, this procedure sets the XDG_RUNTIME_DIR environment variable with its return value in case the environment variable is not set. This behavior can be disabled by binding the set-environment? keyword parameter to #f).