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RtlTestBit function (wdm.h)

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The RtlTestBit routine returns the value of a bit in a bitmap.

Syntax

NTSYSAPI BOOLEAN RtlTestBit(
  [in] PRTL_BITMAP BitMapHeader,
  [in] ULONG       BitNumber
);

Parameters

[in] BitMapHeader

Pointer to the RTL_BITMAP structure that describes the bitmap. This structure must have been initialized by the RtlInitializeBitMap routine.

[in] BitNumber

Specifies the zero-based index of the bit within the bitmap. The routine returns the value of this bit.

Return value

RtlTestBit returns the value of the bit that the BitNumber parameter points to.

Remarks

Callers of RtlTestBit 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, RtlTestBit can be called at any IRQL.

Requirements

Requirement Value
Minimum supported client Available in Windows XP and later versions of Windows.
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)

See also

RTL_BITMAP

RtlInitializeBitMap