COMSTAT structure contains information about the communications device. This structure is meant to be filled by ClearCommError function.

COMSTAT structure contains the following members:

DWORD fCtsHold - wait of the CTS (clear-to-send) signal transmitter to start transmitting data. TRUE - the transmitter is idle.

DWORD fDsrHold - wait of the DSR (data-set-ready) signal transmitter to start transmitting data. TRUE - the transmitter is idle.

DWORD fRlsdHold - wait of the RLSD (receive-line-signal-detect) signal transmitter to start transmitting data. TRUE - the transmitter is idle.

DWORD fXoffHold - wait of the transmitter after the XOFF character is received. TRUE - the transmitter is idle.

DWORD fXoffSent - wait of the transmitter after the XOFF character is transmitted. TRUE - the transmitter is idle. The transmission is stopped when the XOFF character is transmitted to the system which considers the next character as XON regardless of the actual character.

DWORD fEof - wait for reception of EOF (end-of-file) character. TRUE - the character is received.

DWORD fTxim - detection of the character queueing up for the transmission received for the connection device with the help of TransmitCommChar function . The connection device transmits such a character before other characters in the connection device out buffer. TRUE - this character exists.

DWORD fReserved - reserved, not used

DWORD cbInQue - detection of the number of bytes received from the line and not read by the ReadFile function.

DWORD cbOutQue - detection of the number of data bytes transmitted to the communications device by the user for further transmission in the line. It will be a NULL value for nonoverlapped write.