modbus_set_byte_timeout - set timeout between bytes
The modbus_set_byte_timeout() function shall set the timeout interval between
two consecutive bytes of the same message. The timeout is an upper bound on the
amount of time elapsed before select() returns, if the time elapsed is longer
than the defined timeout, an
ETIMEDOUT error will be raised by the
function waiting for a response.
The value of
to_usec argument must be in the range 0 to 999999.
to_usec are zero, this timeout will not be used at all.
In this case, modbus_set_response_timeout() governs the entire handling of the
response, the full confirmation response must be received before expiration of
the response timeout. When a byte timeout is set, the response timeout is only
used to wait for until the first byte of the response.
The function shall return 0 if successful. Otherwise it shall return -1 and set errno.
- EINVAL, The argument
ctxis NULL or
to_usecis larger than 999999.