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include vcd.inc
 
VxDcall VCD_Set_Port_Global
 
The VCD_Set_Port_Global service enables or disables the global handling of a
COM port between multiple virtual machines. When a port is declared to be a
global port, then no contention detection is performed, and no I/O ports are
trapped.
 
This service is provided mainly for a COM port mouse, or other serial
device, where a separate virtual device handles the arbitration of the port
and its interrupts. A Set_Device_Focus control message sent using the
System_Control service can specify which virtual machine should receive
interrupt requests and VCD_Get_Focus returns the current owner of a port.
 
Parameter  Description
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EAX        Specifies the hardware COM port number. It must be in the range
           from 1 to 4.
 
EDX        Specifies whether the port is global (zero) or local (nonzero).
 
Return Value
 
The carry flag is clear if the service is successful. Otherwise, the carry
flag is set if the port is not available.
 
Uses
 
Flags
 
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