DosUnlockSeg

This call unlocks a discardable segment.

Syntax

DosUnlockSeg (Selector)

Parameters

Selector (SEL) - input

Segment selector to be unlocked.

Return Code

rc (USHORT) - return

Return code descriptions are:

• 0 NO_ERROR
• 5 ERROR_ACCESS_DENIED
• 158 ERROR_NOT_LOCKED

Remarks

DosUnlockSeg is called to free memory for possible discard by the system in a low memory situation. The memory being freed is originally allocated by a call to DosAllocSeg or DosAllocHuge with AllocFlags bit 2 set. This memory may have been reallocated by a call to DosReallocSeg or DosReallocHuge after discard by the system.

Allocation and reallocation calls for discardable memory automatically lock the memory for access by the calling process. Thus, to access the segment, the caller does not have to lock the segment with DosLockSeg. Once a discardable segment is unlocked by a DosUnlockSeg request, access to the segment is gained by a successful DosLockSeg request.

DosUnlockSeg may also be used on segments that are non-discardable, in which case it has no effect.

Example Code

C Binding

#define INCL_DOSMEMMGR

USHORT  rc = DosUnlockSeg(Selector);

SEL              Selector;      /* Selector to unlock */

USHORT           rc;            /* return code */

MASM Binding

EXTRN  DosUnlockSeg:FAR
INCL_DOSMEMMGR      EQU 1

PUSH   WORD Selector         ;Selector to unlock
CALL   DosUnlockSeg

Returns WORD