ComMdmClr

ComMdmClr permits a modem-aware application to control modem control signals on a port. Note that the application may control RTS even though a communication port is using hardware flow control. Although controlling RTS is not recommended behavior, it is assumed that the application is aware that it may adversely affect the communications driver's flow control.

The ModemControl parameter is a mask of bits (found in COMIO.H), which indicates which modem control signals should be cleared (de-asserted). Multiple bits may be cleared with a single call, and any unspecified modem control signals are not changed.

Syntax:          err_t far ComMdmClr(handle_t Handle, int ModemControl) 
Parameters:      handle_t Handle - The handle returned via a successful ComOpen.  
                 int ModemControl - An integer mask used to indicate which modem control 
                                    signals are to be cleared (de-asserted) 
Returns:         0 - if successful 
                 Any other value indicates an error condition.  
                 ENOTYOURS - The specified port has not been acquired by the calling 
                             application.  
Comments:        ComOpen() must first be called in order to get a valid handle to the 
                 communications port.
                 
                 This function does NOT check for interactions between hardware flow 
                 control and any user modem signal manipulation.  Be careful not to 
                 accidently interfere with the flow control use of RTS.