DosReallocHuge: Difference between revisions
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This call changes the size of memory originally allocated by [[DosAllocHuge]]. | |||
This call changes the size of memory originally allocated by DosAllocHuge. | |||
==Syntax== | ==Syntax== | ||
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==Return Code== | ==Return Code== | ||
;rc (USHORT) - return:Return code descriptions are: | |||
Return code descriptions are: | * 0 NO_ERROR | ||
* 0 | * 8 ERROR_NOT_ENOUGH_MEMORY | ||
* 8 | *87 ERROR_INVALID_PARAMETER | ||
* 87 | |||
==Remarks== | ==Remarks== | ||
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Normally, segments allocated as shared (AllocFlags bits 0 and 1 were set) cannot be decreased in size. However, if AllocFlags bit 3 was also set, the shared segment's size can be decreased. | Normally, segments allocated as shared (AllocFlags bits 0 and 1 were set) cannot be decreased in size. However, if AllocFlags bit 3 was also set, the shared segment's size can be decreased. | ||
DosReallocHuge is also called to reallocate a segment allocated as discardable (AllocFlags bit 2 set) after the segment is discarded by the system. The call to DosReallocHuge automatically locks the segment for access by the caller, the same as if a DosLockSeg had been issued. | DosReallocHuge is also called to reallocate a segment allocated as discardable (AllocFlags bit 2 set) after the segment is discarded by the system. The call to DosReallocHuge automatically locks the segment for access by the caller, the same as if a [[DosLockSeg]] had been issued. | ||
;Note:This request may be issued from privilege level 2 or 3. However, only a privilege level 3 huge segment is valid. | |||
===Family API Considerations=== | ===Family API Considerations=== | ||
Some options operate differently in the DOS mode than in the OS/2 mode. Therefore, the following restriction applies to DosReallocHuge when coding for the DOS mode: | Some options operate differently in the DOS mode than in the OS/2 mode. Therefore, the following restriction applies to DosReallocHuge when coding for the DOS mode: | ||
*The requested Size value is rounded up to the next paragraph (16-byte). | |||
The requested Size value is rounded up to the next paragraph (16-byte). | |||
==Example Code== | ==Example Code== | ||
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USHORT rc = DosReallocHuge(NumSeg, Size, Selector); | USHORT rc = DosReallocHuge(NumSeg, Size, Selector); | ||
USHORT | USHORT NumSeg; /* Number of 65536-byte segments requested */ | ||
USHORT Size; /* Number of bytes in last segment */ | |||
USHORT | SEL Selector; /* Selector */ | ||
SEL | |||
USHORT | USHORT rc; /* return code */ | ||
</PRE> | </PRE> | ||
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Returns WORD | Returns WORD | ||
</PRE> | </PRE> | ||
[[Category:Dos]] | [[Category:Dos]] | ||
Revision as of 13:48, 24 November 2019
This call changes the size of memory originally allocated by DosAllocHuge.
Syntax
DosReallocHuge (NumSeg, Size, Selector)
Parameters
- NumSeg (USHORT) - input
- Number of 65536 byte segments requested.
- Size (USHORT) - input
- Number of bytes requested in the last non-65536 byte segment. A value of 0 indicates none.
- Selector (SEL) - input
- Selector returned on a previous DosAllocHuge.
Return Code
- rc (USHORT) - return
- Return code descriptions are:
- 0 NO_ERROR
- 8 ERROR_NOT_ENOUGH_MEMORY
- 87 ERROR_INVALID_PARAMETER
Remarks
DosReallocHuge is called to change the size of unshared or shared huge memory allocated by DosAllocHuge. The selector used for this call must be the one returned by the DosAllocHuge request.
Normally, segments allocated as shared (AllocFlags bits 0 and 1 were set) cannot be decreased in size. However, if AllocFlags bit 3 was also set, the shared segment's size can be decreased.
DosReallocHuge is also called to reallocate a segment allocated as discardable (AllocFlags bit 2 set) after the segment is discarded by the system. The call to DosReallocHuge automatically locks the segment for access by the caller, the same as if a DosLockSeg had been issued.
- Note
- This request may be issued from privilege level 2 or 3. However, only a privilege level 3 huge segment is valid.
Family API Considerations
Some options operate differently in the DOS mode than in the OS/2 mode. Therefore, the following restriction applies to DosReallocHuge when coding for the DOS mode:
- The requested Size value is rounded up to the next paragraph (16-byte).
Example Code
C Binding
#define INCL_DOSMEMMGR USHORT rc = DosReallocHuge(NumSeg, Size, Selector); USHORT NumSeg; /* Number of 65536-byte segments requested */ USHORT Size; /* Number of bytes in last segment */ SEL Selector; /* Selector */ USHORT rc; /* return code */
MASM Binding
EXTRN DosReallocHuge:FAR INCL_DOSMEMMGR EQU 1 PUSH WORD NumSeg ;Number of 65536-byte segments requested PUSH WORD Size ;Number of bytes in last segment PUSH WORD Selector ;Selector CALL DosReallocHuge Returns WORD