DosSubAlloc

#define INCL_DOSMEMMGR

USHORT  rc = DosSubAlloc(SegSelector, BlockOffset, Size);

SEL              SegSelector;   /* Segment selector */
PUSHORT          BlockOffset;   /* Block Offset (returned) */
USHORT           Size;          /* Size of requested block */

USHORT           rc;            /* return code */