+Thread_devnull_engraver::Thread_devnull_engraver(){}
+
+ENTER_DESCRIPTION(Thread_devnull_engraver,
+/* descr */ "Kill elements whenever we are Voice called `two' and either "
+"unison, unisilence or soloADue is set.@footnote{On unix systems, the "
+"file @file{/dev/null} is special device: anything written to it is "
+"discarded.}. This engraver works closely together with the part "
+"combiner. When the part combiner notices that two threads are "
+"identical, it tells the @code{Thread_devnull_engraver} to discard "
+"everything in the second thread. "
+,
+/* creats*/ "",
+/* accepts */ "",
+/* acks */ "grob-interface",
+/* reads */ "",
+/* write */ "");