{ Copyright (C) 1981 by Bell Laboratories, Inc., and Whitesmiths Ltd. } .ds n PRIMITIVE .NM close close an open file .SY .Q1 fd : filedesc; close(fd); .Q2 .FU .UL close releases the file descriptor and any associated resources for a file opened by .UL open or .UL create . .BU Behavior is undefined for closing a file that is not open.