This function retrieves modem control-register values.
At a Glance
| Header file: | Winbase.h |
| Windows CE versions: | 1.0 and later |
Syntax
BOOL GetCommModemStatus(HANDLE hFile, LPDWORD lpModemStat);
Parameters
hFile
[in] Handle to the communication device. The CreateFile function returns this handle.
lpModemStat
[out] Long pointer to a 32-bit variable that specifies the current state of the modem control-register values. This parameter can be a combination of the following values:
| Value | Description |
| MS_CTS_ON | The CTS (Clear To Send) signal is on. |
| MS_DSR_ON | The DSR (Data Set Ready) signal is on. |
| MS_RING_ON | The ring indicator signal is on. |
| MS_RLSD_ON | The RLSD (Receive Line Signal Detect) signal is on. |
Return Values
Nonzero indicates success. Zero indicates failure. To get extended error data, call GetLastError.
Remarks
The GetCommModemStatus function is useful when using the WaitCommEvent function to monitor the CTS, DSR, DSR, or ring indicator signals. To detect when these signals change state, use WaitCommEvent and then use GetCommModemStatus to determine the state after a change occurs.
The function fails if the hardware does not support the control-register values.
See Also