The GetCommModemStatus function retrieves modem control-register values.
BOOL GetCommModemStatus(
| HANDLE hFile, | // handle of communications device |
| LPDWORD lpModemStat | // address of control-register values |
| ); |
Parameters
hFile
Identifies the communications device. The CreateFile function returns this handle.
lpModemStat
Points 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 | Meaning |
| 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
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 GetCommModemStatus function is useful when you are using the WaitCommEvent function to monitor the CTS, RLSD, 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