UnmapViewOfFileEx function (memoryapi.h)

Article
02/22/2024

This is an extended version of UnmapViewOfFile that takes an additional flags parameter.

Syntax

BOOL UnmapViewOfFileEx(
  [in] PVOID BaseAddress,
  [in] ULONG UnmapFlags
);

Parameters

[in] BaseAddress

A pointer to the base address of the mapped view of a file that is to be unmapped. This value must be identical to the value returned by a previous call to one of the functions in the MapViewOfFile family.

[in] UnmapFlags

This parameter can be one of the following values.

Value	Meaning
MEM_UNMAP_WITH_TRANSIENT_BOOST 0x00000001	Specifies that the priority of the pages being unmapped should be temporarily boosted (with automatic short term decay) because the caller expects that these pages will be accessed again shortly from another thread. For more information about memory priorities, see the SetThreadInformation(ThreadMemoryPriority) function.
MEM_PRESERVE_PLACEHOLDER 0x00000002	Unmaps a mapped view back to a placeholder (after you've replaced a placeholder with a mapped view using MapViewOfFile3 or MapViewOfFile3FromApp).

Return value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

For more information about the behavior of this function, see the UnmapViewOfFile function.

Requirements

Requirement	Value
Minimum supported client	Windows 8 [desktop apps \| UWP apps]
Minimum supported server	Windows Server 2012 [desktop apps \| UWP apps]
Target Platform	Windows
Header	memoryapi.h (include Windows.h, Memoryapi.h)
Library	onecore.lib
DLL	Kernel32.dll

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