DosSubAlloc

This call suballocates portions of a segment allocated by DosAllocSeg or DosAllocShrSeg, and initialized by DosSubSet.

DosSubAlloc (SegSelector, BlockOffset, Size)

• SegSelector (SEL) - input : Data segment selector that allocates the memory.
• BlockOffset (PUSHORT) - output : Address of the allocated block offset.
• Size (USHORT) - input : Memory block size requested in bytes.

rc (USHORT) - return

Return code descriptions are:

• 0 NO_ERROR
• 311 ERROR_DOSSUB_NOMEM
• 313 ERROR_DOSSUB_BADSIZE

Before a segment allocated by DosAllocSeg or DosAllocShrSeg can be suballocated, it must first be initialized for suballocation by a call to DosSubSet.

Allocation size must be a multiple of four bytes. Otherwise, it is rounded up to a multiple of four bytes. The maximum value for the size parameter is the size that was set with DosSubSet minus 8. Note that no paragraph (16-byte) alignment is required; all requests are serviced on a byte alignment basis.

A suballocated block of memory in a suballocated segment is freed by a call to DosSubFree.

#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 */

EXTRN  DosSubAlloc:FAR
INCL_DOSMEMMGR      EQU 1
 
PUSH   WORD    SegSelector   ;Segment selector
PUSH@  WORD    BlockOffset   ;Block Offset (returned)
PUSH   WORD    Size          ;Size of requested block
CALL   DosSubAlloc

Returns WORD

Text based on http://www.edm2.com/index.php/DosSubAlloc