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include v86mmgr.inc
 
VxDcall V86MMGR_SetLocalA20
 
The V86MMGR_SetLocalA20 service changes the default global behavior of A20
to local if the HMA is global. This service has no effect if the HMA is not
global.
 
This service is only available for Windows 3.1 and later.
 
This service has no parameters.
 
Return Value
 
This service has no return value.
 
Comments
 
When there is a global HMA user, the A20 state associated with the HMA is
also global. Changing A20 in a virtual machine changes it in all virtual
machines simultaneously. Some global A20 users (such as MS-DOS 5.0) desire
that the A20 state be local even though the HMA is global.
 
The V86MMGR device does a V86 Interrupt 2Fh device broadcast which also can
set this state. This service is effectively a duplicate of the broadcast
service which can be called by a virtual device. It is not an error if the
state is set using both methods.
 
Uses
 
Flags
 
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