SCM_SYS_FDSET_P  2577 src/syslib.c     if (!SCM_SYS_FDSET_P(fdset_scm)) Scm_Error("<sys-fdset> required, but got %S", fdset_scm);
SCM_SYS_FDSET_P  2607 src/syslib.c     if (!SCM_SYS_FDSET_P(fdset_scm)) Scm_Error("<sys-fdset> required, but got %S", fdset_scm);
SCM_SYS_FDSET_P  2646 src/syslib.c     if (!SCM_SYS_FDSET_P(fdset_scm)) Scm_Error("<sys-fdset> required, but got %S", fdset_scm);
SCM_SYS_FDSET_P  1321 src/system.c       if (!SCM_SYS_FDSET_P(fds))