EscapeCommFunction
The EscapeCommFunction
function directs a specified communications device to perform an extended
function.
BOOL EscapeCommFunction(
|
HANDLE hFile, |
// handle to
communications device |
|
DWORD dwFunc |
// extended function
to perform |
|
); |
|
Parameters
hFile
Identifies
the communications device. The CreateFile function returns this handle.
dwFunc
Specifies the
code of the extended function to perform. This parameter can be one of the
following values:
|
Value |
Meaning |
|
CLRDTR |
Clears the
DTR (data-terminal-ready) signal. |
|
CLRRTS |
Clears the
RTS (request-to-send) signal. |
|
SETDTR |
Sends the
DTR (data-terminal-ready) signal. |
|
SETRTS |
Sends the
RTS (request-to-send) signal. |
|
SETXOFF |
Causes
transmission to act as if an XOFF character has been received. |
|
SETXON |
Causes
transmission to act as if an XON character has been received. |
|
SETBREAK |
Suspends
character transmission and places the transmission line in a break state
until the ClearCommBreak
function is called (or EscapeCommFunction is called with the CLRBREAK
extended function code). The SETBREAK extended function code is identical to
the SetCommBreak
function. Note that this extended function does not flush data that has not
been transmitted. |
|
CLRBREAK |
Restores
character transmission and places the transmission line in a nonbreak state.
The CLRBREAK extended function code is identical to the ClearCommBreak
function. |
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.
See Also