RtlNumberOfSetBits - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers 
#ifndef _NTRTL_H

NTSYSAPI
ULONG
NTAPI
RtlNumberOfSetBits(
    _In_ PRTL_BITMAP BitMapHeader
    );

#endif

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// wdm.h

NTSYSAPI ULONG RtlNumberOfSetBits(
  [in] PRTL_BITMAP BitMapHeader
);
View the official Windows Driver Kit DDI reference

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This function is documented in Windows Driver Kit.

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Windows Driver Kit DDI reference (nf-wdm-rtlnumberofsetbits)

RtlNumberOfSetBits function

Description

The RtlNumberOfSetBits routine returns a count of the set bits in a given bitmap variable.

Parameters

BitMapHeader [in]

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.

See also

RTL_BITMAP

RtlFindSetBits

RtlInitializeBitMap

RtlNumberOfClearBits

View the official Windows Driver Kit DDI reference

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