SetCommMask function

Specifies a set of events to be monitored for a communications device.

Syntax

BOOL SetCommMask(
  HANDLE hFile,
  DWORD  dwEvtMask
);

Parameters

hFile

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

dwEvtMask

The events to be enabled. A value of zero disables all events. 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_RING
0x0100
A ring indicator was detected.
EV_RLSD
0x0020
The RLSD (receive-line-signal-detect) signal changed state.
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 SetCommMask function specifies 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 get the current event mask of a communications resource, use the GetCommMask function.

Examples

For an example, see Monitoring Communications Events.

Requirements

   
Windows version Windows XP [desktop apps | UWP apps] Windows Server 2003 [desktop apps | UWP apps]
Target Platform Windows
Header winbase.h (include Windows.h)
Library Kernel32.lib
DLL Kernel32.dll

See Also

Communications Functions

Communications Resources

CreateFile

DCB

GetCommMask

SetCommState

WaitCommEvent