COMSTAT structure (winbase.h)

Contains information about a communications device. This structure is filled by the ClearCommError function.

Syntax

typedef struct _COMSTAT {
  DWORD fCtsHold : 1;
  DWORD fDsrHold : 1;
  DWORD fRlsdHold : 1;
  DWORD fXoffHold : 1;
  DWORD fXoffSent : 1;
  DWORD fEof : 1;
  DWORD fTxim : 1;
  DWORD fReserved : 25;
  DWORD cbInQue;
  DWORD cbOutQue;
} COMSTAT, *LPCOMSTAT;

Members

fCtsHold

If this member is TRUE, transmission is waiting for the CTS (clear-to-send) signal to be sent.

fDsrHold

If this member is TRUE, transmission is waiting for the DSR (data-set-ready) signal to be sent.

fRlsdHold

If this member is TRUE, transmission is waiting for the RLSD (receive-line-signal-detect) signal to be sent.

fXoffHold

If this member is TRUE, transmission is waiting because the XOFF character was received.

fXoffSent

If this member is TRUE, transmission is waiting because the XOFF character was transmitted. (Transmission halts when the XOFF character is transmitted to a system that takes the next character as XON, regardless of the actual character.)

fEof

If this member is TRUE, the end-of-file (EOF) character has been received.

fTxim

If this member is TRUE, there is a character queued for transmission that has come to the communications device by way of the TransmitCommChar function. The communications device transmits such a character ahead of other characters in the device's output buffer.

fReserved

Reserved; do not use.

cbInQue

The number of bytes received by the serial provider but not yet read by a ReadFile operation.

cbOutQue

The number of bytes of user data remaining to be transmitted for all write operations. This value will be zero for a nonoverlapped write.

Requirements

Requirement	Value
Minimum supported client	Windows XP
Minimum supported server	Windows Server 2003
Header	winbase.h (include Windows.h)

See also

ClearCommError

ReadFile

TransmitCommChar