ReadConstant ReadInterval ReadMultiplier WriteConstant WriteMultiplier

ReadInterval unsigned long ReadInterval The maximum time allowed to elapse before the arrival of the next byte on the communications line, in milliseconds. If the interval between the arrival of any two bytes exceeds this amount, the ReadFile operation is completed and any buffered data is returned. A value of zero indicates that interval time-outs are not used. A value of MAXDWORD, combined with zero values for both the ReadConstant and ReadMultiplier members, specifies that the read operation is to return immediately with the bytes that have already been received, even if no bytes have been received.