Fdflags

(typename $fdflags
  (flags (@witx repr u16)
    ;;; Append mode: Data written to the file is always appended to the file's end.
    $append
    ;;; Write according to synchronized I/O data integrity completion. Only the data stored in the file is synchronized.
    $dsync
    ;;; Non-blocking mode.
    $nonblock
    ;;; Synchronized read I/O operations.
    $rsync
    ;;; Write according to synchronized I/O file integrity completion. In
    ;;; addition to synchronizing the data stored in the file, the implementation
    ;;; may also synchronously update the file's metadata.
    $sync
  )
)