The following are examples of running rb_objnew.d. The rb_objnew.d script reports the new Ruby objects created (by filename and class) while the script is tracing. Here we see it running while Code/Ruby/func_abc.rb is executed. # rb_objnew.d Tracing... Hit Ctrl-C to end. ^C FILE CLASS COUNT . NoMemoryError 1 . SystemStackError 1 . ThreadGroup 1 . fatal 1 . Object 3 Since this is a simple example, not many objects were allocated - a few for the ruby engine, and three of class Object. No file was associated with these allocations, as they may have been caused by Ruby engine startup, and not necessarily lines of code in the example program.