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include vdd.inc
 
VxDcall VDD_Query_Access
 
The VDD_Query_Access service specifies whether video memory can be accessed.
Virtual devices that call software in the virtual machine use this service
to determine whether a video display error will occur if the software
attempts to access video memory.
 
Parameter  Description
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EBX        Specifies the address of the control block.
 
Return Value
 
The carry flag is clear if a virtual device can access video memory.
 
Comments
 
The virtual device should call this service just before returning to the
virtual machine such as while processing a virtual machine event. If the
video memory cannot be accessed, the virtual device should avoid calling
software that may attempt access even if not calling the software causes
another error, such as leaving the mouse cursor on when the virtual machine
runs in a window.
 
Uses
 
Flags
 
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