+
+/** Check the state of the lock file. If there is an error opening or
+ * reading the lockfile, exit with PS_EXCLUDE. If a stale lock file
+ * cannot be unlinked, complain and try to truncate it to 0 size. If
+ * truncation fails, complain and exit with PS_EXCLUDE. \return
+ * - 0 if no lock is set
+ * - >0 if a fetchmail is running, but not in daemon mode
+ * - <0 if a fetchmail is running in daemon mode.
+ */