cCall [pPortOpen], <<OFFSET32 PortName>, VMId, <OFFSET32 dwError>>
mov pPortInformation, eax
Called by _VCOMM_OpenComm to open a port. Uses the C calling convention.
A port driver should call the _VCOMM_Acquire_Port service to block access to the port when this function is called. If the service fails, the port is already in use and the port driver should not attempt to open it.
The communications resource handle returned by _VCOMM_OpenComm is not necessarily the same as the address returned by this function.
_PORTINFORMATION, _VCOMM_Acquire_Port, _VCOMM_OpenComm