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 |