rb_thread_sleep_forever 2526 ext/tk/tcltklib.c                     rb_thread_sleep_forever();
rb_thread_sleep_forever  448 include/ruby/intern.h void rb_thread_sleep_forever(void);
rb_thread_sleep_forever 4412 process.c      	rb_thread_sleep_forever();
rb_thread_sleep_forever 3748 thread.c       	    rb_thread_sleep_forever();