RUBY_UBF_PROCESS  632 process.c      						 RUBY_UBF_PROCESS, 0);
RUBY_UBF_PROCESS  653 process.c      						     st, RUBY_UBF_PROCESS);
RUBY_UBF_PROCESS 1040 thread.c           if (ubf == RUBY_UBF_IO || ubf == RUBY_UBF_PROCESS) {