rb_exc_set_backtrace   76 eval_error.c   	    rb_exc_set_backtrace(info, bt);
rb_exc_set_backtrace  711 vm_args.c          rb_exc_set_backtrace(exc, at);
rb_exc_set_backtrace 1142 vm_core.h      VALUE rb_exc_set_backtrace(VALUE exc, VALUE bt);