select

This module provides functions to wait for events on streams (select streams which are ready for operations).

Pyboard specifics

Polling is an efficient way of waiting for read/write activity on multiple objects. Current objects that support polling are: pyb.UART, pyb.USB_VCP.

Methods

select.poll()

Create an instance of the Poll class.

select.select(rlist, wlist, xlist[, timeout])

Wait for activity on a set of objects.

This function is provided for compatibility and is not efficient. Usage of Poll is recommended instead.

class Poll

Methods

poll.register(obj[, eventmask])

Register obj for polling. eventmask is logical OR of:

• select.POLLIN - data available for reading
• select.POLLOUT - more data can be written
• select.POLLERR - error occurred

• select.POLLHUP - end of stream/connection termination detected

  eventmask defaults to select.POLLIN | select.POLLOUT.

poll.unregister(obj)

Unregister obj from polling.

poll.modify(obj, eventmask)

Modify the eventmask for obj.

poll.poll([timeout])

Wait for at least one of the registered objects to become ready. Returns list of (obj, event, ...) tuples, event element specifies which events happened with a stream and is a combination of select.POLL* constants described above. There may be other elements in tuple, depending on a platform and version, so don’t assume that its size is 2. In case of timeout, an empty list is returned.

Timeout is in milliseconds.