+If data is already available at the time of the call to
+.BR read (2),
+the call behaves as though the data was received immediately after the call.
+.PP
+POSIX
+.\" POSIX.1-2008 XBD 11.1.7
+does not specify whether the setting of the
+.B O_NONBLOCK
+file status flag takes precedence over the MIN and TIME settings.
+If
+.B O_NONBLOCK
+is set, a
+.BR read (2)
+in noncanonical mode may return immediately,
+regardless of the setting of MIN or TIME.
+Furthermore, if no data is available,
+POSIX permits a
+.BR read (2)
+in noncanonical mode to return either 0, or \-1 with
+.I errno
+set to
+.BR EAGAIN .