Returns a base directory in which to store non-essential, cached data specific to particular user.
On UNIX platforms this is determined using the mechanisms described
XDG Base Directory Specification.
In this case the directory retrieved will be
On Windows it follows XDG Base Directory Specification if
XDG_CACHE_HOME is defined.
XDG_CACHE_HOME is undefined, the directory that serves as a common
repository for temporary Internet files is used instead. A typical path is
C:\Documents and Settings\username\Local Settings\Temporary Internet Files.
See the documentation for
The return value is cached and modifying it at runtime is not supported, as it’s not thread-safe to modify environment variables at runtime.