RtlFindSetBits routine
The RtlFindSetBits routine searches for a range of set bits of a requested size within a bitmap.
Syntax
ULONG RtlFindSetBits( _In_ PRTL_BITMAP BitMapHeader, _In_ ULONG NumberToFind, _In_ ULONG HintIndex );
Parameters
- BitMapHeader [in]
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A pointer to the RTL_BITMAP structure that describes the bitmap. This structure must have been initialized by the RtlInitializeBitMap routine.
- NumberToFind [in]
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Specifies how many contiguous set bits will satisfy this request.
- HintIndex [in]
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Specifies a zero-based bit position around which to start looking for a set bit range of the given size.
Return value
RtlFindSetBits either returns the zero-based starting bit index for a set bit range of the requested size, or it returns 0xFFFFFFFF if it cannot find such a range within the given bitmap variable.
Remarks
For a successful call, the returned bit position is not necessarily equivalent to the given HintIndex. If necessary, RtlFindSetBits searches the whole bitmap to locate a set bit range of the requested size. However, it starts searching for the requested range near HintIndex, so callers can find such a range more quickly when they can supply appropriate hints about where to start looking.
Callers of RtlFindSetBits must be running at IRQL <= APC_LEVEL if the memory that contains the bitmap variable is pageable or the memory at BitMapHeader is pageable. Otherwise, RtlFindSetBits can be called at any IRQL.
Requirements
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Version | Available starting with Windows 2000. |
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IRQL | <= APC_LEVEL (See Remarks section) |
See also
- RtlAreBitsSet
- RTL_BITMAP
- RtlClearBits
- RtlFindClearBits
- RtlFindSetBitsAndClear
- RtlInitializeBitMap
- RtlNumberOfSetBits
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Build date: 5/22/2013
