cCall [pPortSetModemStatusShadow], <hPort, dwEventMask
<OFFSET32 MSRShadow>>
or eax, eax
jz error_handler
Sets the location of the modem status shadow for a port. The port driver updates the byte at this location whenever the modem status register changes. Uses the C calling convention.
When a port is opened, the modem status shadow is the bMSRShadow field of the _PORTDATA structure.
VCOMM calls this function when the VCOMM_PM_API_SetMSRShadow protected-mode API is called. This enables the 16-bit Windows communications driver to set the modem status shadow to a location in the system VM. There is no equivalent VCOMM service.
_PORTDATA, _PORTINFORMATION, PortOpen, VCOMM_PM_API_SetMSRShadow