IOCTL Requests Overview

Serial Ports Monitor ActiveX Control supports the following standard IOCTL requests:

FunctionBrief Description
IOCTL_SERIAL_CLEAR_STATS This request clears the performance statistics for a serial device
IOCTL_SERIAL_CLR_DTRThis request clears the data terminal ready control signal (DTR)
IOCTL_SERIAL_CLR_RTSThis request clears the request to send control signal (RTS)
IOCTL_SERIAL_CONFIG_SIZE This request returns information about configuration size
IOCTL_SERIAL_GET_BAUD_RATEThis request returns the baud rate that is currently set for a serial device
IOCTL_SERIAL_GET_CHARSThis request returns the special characters that Serial Port uses with handshake flow control
IOCTL_SERIAL_GET_COMMSTATUSThis request returns information about the communication status of a serial device
IOCTL_SERIAL_GET_DTRRTSThis request returns information about the data terminal ready control signal (DTR) and the request to send control signal (RTS)
IOCTL_SERIAL_GET_HANDFLOW This request returns information about the configuration of the handshake flow control set for a serial device
IOCTL_SERIAL_GET_LINE_CONTROL This request returns information about the line control set for a serial device. The line control parameters include the number of stop bits, data bits, and the parity
IOCTL_SERIAL_GET_MODEM_CONTROLThis request returns the value of the modem control register
IOCTL_SERIAL_GET_MODEMSTATUSThis request updates the modem status, and returns the value of the modem status register before the update
IOCTL_SERIAL_GET_PROPERTIESThis request returns information about the capabilities of a serial device
IOCTL_SERIAL_GET_STATSThis request returns information about the performance of a serial device. The statistics includes the number of characters transmitted and received, and useful error statistics. The driver continuously increments performance values.
IOCTL_SERIAL_GET_TIMEOUTSThis request returns the timeouts values that Serial driver uses with read and write requests
IOCTL_SERIAL_GET_WAIT_MASKThis request returns the event wait mask that is currently set on a serial device
IOCTL_SERIAL_IMMEDIATE_CHARThis request causes a specified character to be transmitted as soon as possible. The immediate character request completes immediately after any other write that might be in progress. Only one immediate character request can be pending at a time
IOCTL_SERIAL_LSRMST_INSERTThis request enables or disables the insertion of information about line status and modem status in the receive data stream
IOCTL_SERIAL_PURGEThis request cancels the specified requests and deletes data from the specified buffers
IOCTL_SERIAL_RESET_DEVICEThis request resets a serial device
IOCTL_SERIAL_SET_BAUD_RATEThis request sets the baud rate on a serial device
IOCTL_SERIAL_SET_BREAK_OFFThis request sets the line control break signal inactive
IOCTL_SERIAL_SET_BREAK_ONThis request sets the line control break signal active
IOCTL_SERIAL_SET_CHARSThis request sets the special characters that Serial Port uses for handshake flow control
IOCTL_SERIAL_SET_DTRThis request sets DTR (data terminal ready)
IOCTL_SERIAL_SET_FIFO_CONTROLThis request sets the FIFO control register (FCR)
IOCTL_SERIAL_SET_HANDFLOWThis request sets the configuration of handshake flow control
IOCTL_SERIAL_SET_LINE_CONTROLThis request sets the line control register (LCR). The line control register controls the data size, the number of stop bits, and the parity
IOCTL_SERIAL_SET_MODEM_CONTROLThis request sets the modem control register
IOCTL_SERIAL_SET_QUEUE_SIZEThis sets the size of the internal receive buffer. If the requested size is greater than the current receive buffer size, a new receive buffer is created. Otherwise, the receive buffer is not changed
IOCTL_SERIAL_SET_RTSThis request sets RTS (request to send)
IOCTL_SERIAL_SET_TIMEOUTSThis request sets the time-out values that the driver uses with read and write requests
IOCTL_SERIAL_SET_WAIT_MASKThis request configures Serial to notify a client after the occurrence of any one of a specified set of wait events
IOCTL_SERIAL_SET_XOFFThis request emulates the reception of an XOFF character. The request stops reception of data
IOCTL_SERIAL_SET_XONThis request emulates the reception of a XON character, which restarts reception of data
IOCTL_SERIAL_WAIT_ON_MASKThis request is used to wait for the occurrence of any wait event specified by using an IOCTL_SERIAL_SET_WAIT_MASK request
IOCTL_SERIAL_XOFF_COUNTERThis request sets an XOFF counter. An XOFF counter request supports clients that use software to emulate hardware handshake flow control