DosLockSeg
Bindings: C, MASM
This call locks a discardable segment in memory.
DosLockSeg (Selector)
Selector (SEL) - input
Selector of the segment to be locked.
rc (USHORT) - return
Return code descriptions are:
0 NO_ERROR
5 ERROR_ACCESS_DENIED
157 ERROR_DISCARDED
Remarks
Discardable segments are useful for holding objects that are accessed for
short periods of time and that can be regenerated quickly if discarded.
Examples are cache buffers for a data base package, saved bitmap images
for obscured windows or precomputed display images for a word processing
application.
Discardable memory is allocated by a call to DosAllocSeg or DosAllocHuge
with AllocFlags bit 2 set. Upon allocation, the memory is automatically
locked for access by the allocating process and cannot be discarded.
After the segment is unlocked by a DosUnlockSeg request, the memory can
be discarded by the memory manager to remedy a low memory situation.
Once memory is discarded, a DosLockSeg call returns ERROR_DISCARDED.
The memory is reallocated by a call to DosReallocSeg or DosReallocHuge.
The reallocation request automatically locks the memory.
Memory allocated as discardable by a DosAllocSeg or DosAllocHuge request
may also have been designated as shareable. Sharing processes that access
the discardable shared memory with DosGetSeg have to lock the memory by
calling DosLockSeg. See DosGetSeg for more information.
DosLockSeg and DosUnlockSeg calls may be nested. If DosLockSeg is
called multiple times to lock a segment, the same number of calls must be
made to DosUnlockSeg before the segment is unlocked. However, if a
segment is locked 255 times, it becomes permanently locked. Additional
calls to DosLockSeg and DosUnlockSeg have no effect on the segment's
locked state.
This function is used on segments that have been allocated through
DosAllocSeg with AllocFlags bit 2 (0100B) set. It may be also used on
segments that are non-discardable, in which case it has no effect.
Created using Inf-PHP v.2 (c) 2003 Yuri Prokushev
Created using Inf-HTML v.0.9b (c) 1995 Peter Childs