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docs: USB_VCP: Always in non-blocking mode, clarify stream method returns.

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They return None if no data available.
This commit is contained in:
Paul Sokolovsky 2015-10-25 13:24:29 +03:00
parent cf6daa0966
commit b7ab70c71c
1 changed files with 7 additions and 4 deletions
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11
docs/library/pyb.USB_VCP.rst
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@ -43,12 +43,14 @@ Methods
Read at most ``nbytes`` from the serial device and return them as a
bytes object. If ``nbytes`` is not specified then the method acts as
``readall()``.
``readall()``. USB_VCP stream implicitly works in non-blocking mode,
so if no pending data available, this method will return immediately
with ``None`` value.
.. method:: usb_vcp.readall()
Read all available bytes from the serial device and return them as
a bytes object.
a bytes object, or ``None`` if no pending data available.
.. method:: usb_vcp.readinto(buf, [maxlen])
@ -57,14 +59,15 @@ Methods
If ``maxlen`` is given and then at most ``min(maxlen, len(buf))`` bytes
are read.
Returns the number of bytes read and stored into ``buf``.
Returns the number of bytes read and stored into ``buf`` or ``None``
if no pending data available.
.. method:: usb_vcp.readline()
Read a whole line from the serial device.
Returns a bytes object containing the data, including the trailing
newline character.
newline character or ``None`` if no pending data available.
.. method:: usb_vcp.readlines()