GetCommMask function

Retrieves the value of the event mask for a specified communications device.

Syntax

BOOL WINAPI GetCommMask(
  _In_  HANDLE  hFile,
  _Out_ LPDWORD lpEvtMask
);

Parameters

hFile [in]

A handle to the communications device. The CreateFile function returns this handle.

lpEvtMask [out]

A pointer to the variable that receives a mask of events that are currently enabled. This parameter can be one or more of the following values.

Value	Meaning
EV_BREAK 0x0040	A break was detected on input.
EV_CTS 0x0008	The CTS (clear-to-send) signal changed state.
EV_DSR 0x0010	The DSR (data-set-ready) signal changed state.
EV_ERR 0x0080	A line-status error occurred. Line-status errors are CE_FRAME, CE_OVERRUN, and CE_RXPARITY.
EV_EVENT1 0x0800	An event of the first provider-specific type occurred.
EV_EVENT2 0x1000	An event of the second provider-specific type occurred.
EV_PERR 0x0200	A printer error occurred.
EV_RING 0x0100	A ring indicator was detected.
EV_RLSD 0x0020	The RLSD (receive-line-signal-detect) signal changed state.
EV_RX80FULL 0x0400	The receive buffer is 80 percent full.
EV_RXCHAR 0x0001	A character was received and placed in the input buffer.
EV_RXFLAG 0x0002	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 0x0004	The last character in the output buffer was sent.

 

Return value

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

See also

Communications Functions

Communications Resources

CreateFile

DCB

SetCommMask

WaitCommEvent