GetCommMask

The GetCommMask function retrieves the value of the event mask for a specified communications device.

BOOL GetCommMask(
  HANDLE hFile,      // handle to communications device
  LPDWORD lpEvtMask  // event mask
);

Parameters

hFile

[in] Handle to the communications device. The CreateFile function returns this handle.

lpEvtMask

[out] Pointer to the variable to be filled with a mask of events that are currently enabled. This parameter can be one or more of the following values.

Value	Meaning
EV_BREAK	A break was detected on input.
EV_CTS	The CTS (clear-to-send) signal changed state.
EV_DSR	The DSR (data-set-ready) signal changed state.
EV_ERR	A line-status error occurred. Line-status errors are CE_FRAME, CE_OVERRUN, and CE_RXPARITY.
EV_EVENT1	An event of the first provider-specific type occurred.
EV_EVENT2	An event of the second provider-specific type occurred.
EV_PERR	A printer error occurred.
EV_RING	A ring indicator was detected.
EV_RLSD	The RLSD (receive-line-signal-detect) signal changed state.
EV_RX80FULL	The receive buffer is 80 percent full.
EV_RXCHAR	A character was received and placed in the input buffer.
EV_RXFLAG	The event character was received and placed in the input buffer. The event character is specified in the device's DCB structure, which is applied to a serial port by using the SetCommState function.
EV_TXEMPTY	The last character in the output buffer was sent.

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

The GetCommMask function uses a mask variable to indicate the set of events that can be monitored for a particular communications resource. A handle to the communications resource can be specified in a call to the WaitCommEvent function, which waits for one of the events to occur. To modify the event mask of a communications resource, use the SetCommMask function.

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Winbase.h; include Windows.h.
  Library: Use Kernel32.lib.

See Also

Communications Overview, Communication Functions, CreateFile, DCB, SetCommMask, WaitCommEvent