file_scm         4217 src/extlib.c     ScmObj file_scm;
file_scm         4225 src/extlib.c     file_scm = SCM_ARGREF(0);
file_scm         4226 src/extlib.c     if (!SCM_STRINGP(file_scm)) Scm_Error("string required, but got %S", file_scm);
file_scm         4227 src/extlib.c     file = SCM_STRING(file_scm);