RtlNumberOfSetBits function (wdm.h)
The RtlNumberOfSetBits routine returns a count of the set bits in a given bitmap variable.
Syntax
NTSYSAPI ULONG RtlNumberOfSetBits(
[in] PRTL_BITMAP BitMapHeader
);
Parameters
[in] BitMapHeader
A pointer to the RTL_BITMAP structure that describes the bitmap. This structure must have been initialized by the RtlInitializeBitMap routine.
Return value
RtlNumberOfSetBits returns a count of the bits that are currently set.
Remarks
Callers of RtlNumberOfSetBits 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, RtlNumberOfSetBits 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 (kernel mode); Ntdll.dll (user mode) |
| IRQL | <= APC_LEVEL (See Remarks section) |