Relock Real Mode Region

Call With

AX = 0603H
BX:CX = starting linear address of memory to relock
SI:DI = size of region to relock (bytes)

Returns

if function successful
Carry flag = clear

if function unsuccessful
Carry flag = set
AX = error code

8002H	invalid state (region not marked as pageable)
8013H	physical memory unavailable
8025H	invalid linear address (region is above 1 MB boundary)

Notes

• If the function returns an error, none of the memory has been relocked.

• If the specified region overlaps part of a page at the beginning or end of the region, the page(s) will not be relocked.

• This function is ignored by DPMI implementations that do not support virtual memory; the function will return the Carry flag clear to indicate success, but has no other effect. DPMI hosts which support virtual memory may also choose to ignore this function, but such hosts must be able to handle page faults transparently at arbitrary points during a client's execution, including within interrupt and exception handlers.

• If Function 0602H is implemented as a "no-operation" on a particular DPMI host, this function will likewise do nothing. In other words, this function should not be used to lock memory, but only to restore the default state of the host's conventional memory locking.