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include vcd.inc
 
VxDcall VCD_Get_Focus
 
The VCD_Get_Focus service returns the virtual machine handle of the current
owner of a COM port. Focus can be set with a Set_Device_Focus control
message sent using the System_Control service and specifying the VCD
device.
 
Parameter  Description
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EAX        Specifies the hardware COM port number. It must be in the range 1
           to 4.
 
Return Value
 
If the carry flag is clear, the EBX register contains virtual machine handle
or zero if there is no owner.
 
The carry flag is set if the port is not available.
 
Uses
 
EBX, Flags
 
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