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====== DosSubFree ======

This call frees memory previously allocated by DosSubAlloc. 

===== Syntax =====
<code c>
DosSubFree (SegSelector, BlockOffset, Size)
</code>

===== Parameters =====

  * SegSelector ([[SEL]]) - input : Data segment selector.
  * BlockOffset ([[USHORT]]) - input : Memory block offset. The value specified must equal the BlockOffset returned on a previous DosSubAlloc call.
  * Size ([[USHORT]]) - input :  Size, in bytes, of the block to be freed.

===== Return Code =====

rc ([[USHORT]]) - return

Return code descriptions are:

  * 0          NO_ERROR 
  * 312        ERROR_DOSSUB_OVERLAP 
  * 313        ERROR_DOSSUB_BADSIZE

===== Remarks =====

DosSubFree specifies the offset of a block of memory previously suballocated by a [[DosSubAlloc]] request. If the block specified overlaps memory in the segment that is not suballocated, an error is returned. Like [[DosSubAlloc]], the size parameter must be a multiple of four bytes; otherwise, it is rounded up to a multiple of four bytes.

The allocated segment is freed by calling [[DosFreeSeg]]. 

===== Example Code =====

==== C Binding ====

<code c>
#define INCL_DOSMEMMGR

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

SEL              SegSelector;   /* Segment selector */
USHORT           BlockOffset;   /* Offset of memory block to free */
USHORT           Size;          /* Size of block in bytes */

USHORT           rc;            /* return code */
</code>

==== MASM Binding ====

<code asm>
EXTRN  DosSubFree:FAR
INCL_DOSMEMMGR      EQU 1

PUSH   WORD    SegSelector   ;Segment selector
PUSH   WORD    BlockOffset   ;Offset of memory block to free
PUSH   WORD    Size          ;Size of block in bytes
CALL   DosSubFree
</code>
Returns WORD

===== Note =====

Text based on [[http://www.edm2.com/index.php/DosSubFree]]

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