RtlAreBitsClear function (wdm.h)
The RtlAreBitsClear routine determines whether a given range of bits within a bitmap variable is clear.
Syntax
NTSYSAPI BOOLEAN RtlAreBitsClear(
[in] PRTL_BITMAP BitMapHeader,
[in] ULONG StartingIndex,
[in] ULONG Length
);
Parameters
[in] BitMapHeader
A pointer to the RTL_BITMAP structure that describes the bitmap. This structure must have been initialized by the RtlInitializeBitMap routine.
[in] StartingIndex
Specifies the start of the bit range to be tested. This is a zero-based value indicating the position of the first bit in the range.
[in] Length
Specifies how many bits to test.
Return value
RtlAreBitsClear returns TRUE if Length consecutive bits beginning at StartingIndex are clear (that is, all the bits from StartingIndex to (StartingIndex + Length) -1). It returns FALSE if any bit in the given range is set, if the given range is not a proper subset of the bitmap, or if the given Length is zero.
Remarks
Callers of RtlAreBitsClear 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, RtlAreBitsClear 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) |