GetCommModemStatus
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4/8/2010
This function retrieves modem control-register values.
Syntax
BOOL GetCommModemStatus(
HANDLE hFile,
LPDWORD lpModemStat
);
Parameters
- hFile
[in] Handle to the communication device, returned by the CreateFile function.
lpModemStat
[out] Long pointer to a 32-bit variable that specifies the current state of the modem control-register values. The following table shows possible values.Value Description MS_CTS_ON
The clear-to-send (CTS) signal is on.
MS_DSR_ON
The data-set-ready (DSR) signal is on.
MS_RING_ON
The ring indicator signal is on.
MS_RLSD_ON
The receive-line-signal-detect (RLSD) signal is on.
Return Value
Nonzero indicates success. Zero indicates failure. To obtain extended error data, call the GetLastError function.
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.
Requirements
| Header | winbase.h |
| Library | Serdev.lib |
| Windows Embedded CE | Windows CE 1.0 and later |
| Windows Mobile | Windows Mobile Version 5.0 and later |
See Also
Reference
Serial Communications Functions
WaitCommEvent