PortOpen

cCall [pPortOpen], <<OFFSET32 PortName>, VMId, <OFFSET32 dwError>>
mov     pPortInformation, eax

Called by _VCOMM_OpenComm to open a port. Uses the C calling convention.

• Returns the address of a _PORTINFORMATION structure if successful, NULL otherwise. VCOMM specifies the address in all subsequent calls to port-driver functions for the port.

PortName

Address of a null-terminated string specifying the port name, or NULL if the port should be opened by number.

VMId

Handle of the virtual machine (VM) that owns the port.

dwError

Address of a 32-bit value that receives an error code if the return value is NULL. This parameter is ignored if the return value is not NULL.

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.

See also _PORTINFORMATION, _VCOMM_Acquire_Port, _VCOMM_OpenComm