Psychtoolbox>IOPort.{mex*} subfunction

Read data from device, specified by ‘handle’.
Returned ‘data’ will be a row vector of read data bytes. ‘when’ will be a
receive timestamp of when the data read was complete. ‘errmsg’ will be a human
readable char string with an error message if any error occured, otherwise an
empty string. The optional flag ‘blocking’ if set to 0 will ask the read
function to not block, but return immediately: The read function will return
whatever amount of data is currently available in the internal input queue, but
at most ‘amount’ bytes if ‘amount’ is specified. If no data is available, it
will return an empty matrix. This is the default.
If ‘blocking’ is set to 1, you must specify the ‘amount’ of bytes to receive and
the function will wait until that exact amount of data is available, then return
it.Even in blocking mode, the function will return if no data becomes available
within the time period specified by the configuration setting ‘ReadTimeout’ (see
help for ‘OpenSerialPort’ for description). In some situations, the read
function may return less data than requested, e.g., in specific error cases,
where a read could only get partially satisfied.

###See also: ‘Write’, ‘OpenSerialPort’, ‘ConfigureSerialPort’