SERIAL_STATUS structure (ntddser.h)

The SERIAL_STATUS structure contains status information about the serial port.

Syntax

typedef struct _SERIAL_STATUS {
  ULONG   Errors;
  ULONG   HoldReasons;
  ULONG   AmountInInQueue;
  ULONG   AmountInOutQueue;
  BOOLEAN EofReceived;
  BOOLEAN WaitForImmediate;
} SERIAL_STATUS, *PSERIAL_STATUS;

Members

Errors

A set of flags to indicate the receive errors that have occurred in the input stream. This member is set to zero or to the bitwise-OR of one or more of the following flag bits.

Flag name	Meaning
SERIAL_ERROR_QUEUEOVERRUN	The serial controller driver's internal input buffer was overrun by data received from the input stream. Either the input buffer is full, or a character was received after the EOF (end of file) character.
SERIAL_ERROR_OVERRUN	The hardware receive FIFO was overrun by data received from the input stream.
SERIAL_ERROR_BREAK	A break condition occurred on the input line.
SERIAL_ERROR_PARITY	A parity error was detected in a byte received from the input stream.
SERIAL_ERROR_FRAMING	A framing error was detected in the bytes received from the input stream.

 

After the serial controller driver supplies the accumulated SERIAL_ERROR_XXX flags to satisfy an IOCTL_SERIAL_GET_COMMSTATUS request, the driver resets the flags to zero.

HoldReasons

A set of flags to indicate the reasons that the serial port is currently waiting to transmit bytes to the output stream. This member is set to zero or to the bitwise-OR of one or more of the following flag bits.

Flag name	Meaning
SERIAL_TX_WAITING_FOR_CTS	Waiting for the CTS (clear to send) signal.
SERIAL_TX_WAITING_FOR_DSR	Waiting for the DSR (data set ready) signal.
SERIAL_TX_WAITING_FOR_DCD	Waiting for the DCD (data carrier detect) signal.
SERIAL_TX_WAITING_FOR_XON	Waiting for the XON (transmit on) signal.
SERIAL_TX_WAITING_ON_BREAK	Sending a break (spacing value) signal.
SERIAL_TX_WAITING_XOFF_SENT	Sent an XOFF (transmit off) signal. This signal marks the end of transmission from the serial port, which then waits for the device on the other end of the line to start transmitting. The other device receives the transmitted XOFF signal as an XON signal.

 

HoldReasons is zero if the serial port has no reason to stop transmitting bytes.

AmountInInQueue

The number of bytes of data received from the serial port that are currently available to be read from the input buffer.

AmountInOutQueue

The number of bytes of transmit data that are currently waiting to be written from the output buffer to the serial port.

EofReceived

Whether an EOF (end of file) character has been received. This member is TRUE if an EOF has been received. Otherwise, it is FALSE. The EOF character marks the end of the input stream.

WaitForImmediate

Whether the serial port is waiting to transmit an immediate character. This member is TRUE if the serial port is waiting to transmit an immediate character. Otherwise, it is FALSE. Transmission of an immediate character might be delayed if any flag bit other than SERIAL_TX_WAITING_FOR_XON is set in the HoldReasons member. For more information about immediate characters, see IOCTL_SERIAL_IMMEDIATE_CHAR.

Remarks

This structure is used by the IOCTL_SERIAL_GET_COMMSTATUS request.

Requirements

Requirement	Value
Header	ntddser.h

See also

IOCTL_SERIAL_GET_COMMSTATUS

IOCTL_SERIAL_IMMEDIATE_CHAR