Expand Minimize

RtlFindLongestRunClear routine

The RtlFindLongestRunClear routine searches for the largest contiguous range of clear bits within a given bitmap.

Syntax


ULONG RtlFindLongestRunClear(
  _In_   PRTL_BITMAP BitMapHeader,
  _Out_  PULONG StartingIndex
);

Parameters

BitMapHeader [in]

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

StartingIndex [out]

Pointer to a variable in which the starting index of the longest clear run in the bitmap is returned. This is a zero-based value indicating the bit position of the first clear bit in the returned range.

Return value

RtlFindLongestRunClear returns either the number of bits in the run beginning at StartingIndex, or zero if it cannot find a run of clear bits within the bitmap.

Remarks

A returned run can have a single clear bit.

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

Requirements

Version

Available starting with Windows 2000.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

Library

Ntoskrnl.lib

IRQL

<= APC_LEVEL (See Remarks section)

See also

RtlAreBitsClear
RTL_BITMAP
RtlFindClearBits
RtlFindClearRuns
RtlFindFirstRunClear
RtlFindLastBackwardRunClear
RtlFindLongestRunClear
RtlFindNextForwardRunClear
RtlSetBits
RtlInitializeBitMap
RtlNumberOfClearBits

 

 

Send comments about this topic to Microsoft

Show:
© 2014 Microsoft