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en:docs:fapi:dosfreeseg [2018/08/30 16:27] – created prokushev | en:docs:fapi:dosfreeseg [2021/09/17 05:57] – prokushev | ||
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+ | {{page> | ||
+ | ====== DosFreeSeg ====== | ||
This call deallocates a memory segment. | This call deallocates a memory segment. | ||
- | ==Syntax== | + | ===== Syntax ===== |
- | | + | |
- | ==Parameters== | + | <code c> |
- | ;Selector ([[SEL]]) - input : Selector of the segment to be freed. | + | DosFreeSeg (Selector) |
+ | </ | ||
+ | |||
+ | ===== Parameters ===== | ||
+ | |||
+ | | ||
+ | |||
+ | ===== Return Code ===== | ||
+ | |||
+ | rc (USHORT) - return | ||
- | ==Return Code== | ||
- | rc (USHORT) - return | ||
Return code descriptions are: | Return code descriptions are: | ||
- | * 0 | + | |
- | * 5 | + | * 5 |
- | * 212 | + | * 212 |
+ | |||
+ | ===== Remarks ===== | ||
- | ==Remarks== | ||
DosFreeSeg frees selectors to segments returned by allocation calls to [[DosAllocSeg]], | DosFreeSeg frees selectors to segments returned by allocation calls to [[DosAllocSeg]], | ||
- | When allocated memory is shared, all selectors to the shared memory must be freed before the memory is deallocated. For example, if memory allocated by DosAllocSeg or DosAllocHuge has been given to another process with [[DosGiveSeg]], | + | When allocated memory is shared, all selectors to the shared memory must be freed before the memory is deallocated. For example, if memory allocated by [[DosAllocSeg]] or [[DosAllocHuge]] has been given to another process with [[DosGiveSeg]], |
+ | |||
+ | DosFreeSeg decrements the reference count for named shared segments allocated by [[DosAllocShrSeg]]. Access to the segment with [[DosGetShrSeg]] increments this count. When the count is 0, the memory is deallocated. | ||
+ | |||
+ | ==== Family API Considerations ==== | ||
- | DosFreeSeg decrements the reference count for named shared segments allocated by DosAllocShrSeg. Access to the segment with [[DosGetShrSeg]] increments this count. When the count is 0, the memory is deallocated. | ||
- | ===Family API Considerations=== | ||
Some options operate differently in the DOS mode than in OS/2 mode. Therefore, the following restriction applies to DosFreeSeg when coding for the DOS mode: | Some options operate differently in the DOS mode than in OS/2 mode. Therefore, the following restriction applies to DosFreeSeg when coding for the DOS mode: | ||
If DosFreeSeg is issued on a CSAliased segment it deallocates the associated memory. This is inconsistent with the OS/2 mode, because DosFreeSeg must be performed on both the original and CSAliased selectors. | If DosFreeSeg is issued on a CSAliased segment it deallocates the associated memory. This is inconsistent with the OS/2 mode, because DosFreeSeg must be performed on both the original and CSAliased selectors. | ||
- | ==Example Code== | + | ===== Example Code ===== |
- | ===C Binding=== | + | |
- | < | + | |
- | #define INCL_DOSMEMMGR | + | |
- | USHORT | + | ==== C Binding ==== |
- | SEL Selector; | + | <code c> |
- | + | #define INCL_DOSMEMMGR | |
- | USHORT | + | |
- | </PRE> | + | USHORT |
+ | |||
+ | | ||
+ | |||
+ | USHORT | ||
+ | </code> | ||
This example allocates a segment of 30,250 bytes and then discards the segment. | This example allocates a segment of 30,250 bytes and then discards the segment. | ||
- | <PRE> | ||
- | #define INCL_DOSMEMMGR | ||
- | |||
- | #define NUMBER_OF_BYTES 30250 | ||
- | #define ALLOC_FLAG SEG_GETTABLE | ||
- | |||
- | SEL Selector; | ||
- | USHORT rc; | ||
- | rc = DosAllocSeg(NUMBER_OF_BYTES, | + | <code c> |
- | & | + | #define INCL_DOSMEMMGR |
- | ALLOC_FLAG); | + | |
+ | #define NUMBER_OF_BYTES 30250 | ||
+ | #define ALLOC_FLAG SEG_GETTABLE | ||
+ | |||
+ | SEL Selector; | ||
+ | USHORT rc; | ||
+ | |||
+ | rc = DosAllocSeg(NUMBER_OF_BYTES, | ||
+ | & | ||
+ | | ||
rc = DosFreeSeg(Selector); | rc = DosFreeSeg(Selector); | ||
- | </PRE> | + | </code> |
- | ===MASM Binding=== | + | |
- | < | + | |
- | EXTRN DosFreeSeg: | + | |
- | INCL_DOSMEMMGR | + | |
- | PUSH | + | ==== MASM Binding ==== |
- | CALL | + | |
+ | <code asm> | ||
+ | EXTRN DosFreeSeg: | ||
+ | INCL_DOSMEMMGR | ||
+ | | ||
+ | PUSH | ||
+ | CALL | ||
+ | </ | ||
Returns WORD | Returns WORD | ||
- | </ | ||
+ | ===== Note ===== | ||
- | ====== Note ====== | ||
Text based on http:// | Text based on http:// |