RtlClearBits function (wdm.h)
The RtlClearBits routine sets all bits in the specified range of bits in the bitmap to zero.
Syntax
NTSYSAPI VOID RtlClearBits(
[in] PRTL_BITMAP BitMapHeader,
[in] ULONG StartingIndex,
[in] ULONG NumberToClear
);
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
The index of the first bit in the bit range that is to be cleared. If the bitmap contains N bits, the bits are numbered from 0 to N-1.
[in] NumberToClear
Specifies how many bits to clear. If the bitmap contains N bits, this parameter can be a value in the range 1 to (N - StartingIndex).
Return value
This routine does not return a value.
Remarks
If the NumberToClear parameter is zero, RtlClearBits simply returns control without clearing any bits.
The sum (StartingIndex + NumberToClear) must not exceed the SizeOfBitMap parameter value specified in the RtlInitializeBitMap call that initialized the bitmap.
Callers of RtlClearBits must be running at IRQL <= APC_LEVEL if the memory that contains the bitmap is pageable or the memory at BitMapHeader is pageable. Otherwise, RtlClearBits 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.) |