RtlFindLongestRunClear function (wdm.h)
The RtlFindLongestRunClear routine searches for the largest contiguous range of clear bits within a given bitmap.
Syntax
NTSYSAPI ULONG RtlFindLongestRunClear(
[in] PRTL_BITMAP BitMapHeader,
[out] PULONG StartingIndex
);
Parameters
[in] BitMapHeader
A pointer to the RTL_BITMAP structure that describes the bitmap. This structure must have been initialized by the RtlInitializeBitMap routine.
[out] StartingIndex
Pointer to a variable in which the starting index of the longest clear run in the bitmap is returned. This is a zero-based value indicating the bit position of the first clear bit in the returned range.
Return value
RtlFindLongestRunClear returns either the number of bits in the run beginning at StartingIndex, or zero if it cannot find a run of clear bits within the bitmap.
Remarks
A returned run can have a single clear bit.
Callers of RtlFindLongestRunClear 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, RtlFindLongestRunClear can be called at any IRQL.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available starting with Windows 2000. |
| Target Platform | Universal |
| Header | wdm.h (include Wdm.h, Ntddk.h, Ntifs.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | <= APC_LEVEL (See Remarks section) |