SetCommMask
The SetCommMask
function specifies a set of events to be monitored for a communications device.
BOOL SetCommMask(
|
HANDLE hFile, |
// handle of
communications device |
|
DWORD dwEvtMask |
// mask that
identifies enabled events |
|
); |
|
Parameters
hFile
Identifies
the communications device. The CreateFile function returns this handle.
dwEvtMask
Specifies the
events to be enabled. A value of zero disables all events. This parameter can
be a combination 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_RING |
A ring
indicator was detected. |
|
EV_RLSD |
The RLSD
(receive-line-signal-detect) signal changed state. |
|
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 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.
If SetCommMask
is called for a communications resource while an overlapped wait is pending for
that resource, WaitCommEvent returns an error.
See Also