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MmUnmapIoSpace function (wdm.h)

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The MmUnmapIoSpace routine unmaps a specified range of physical addresses previously mapped by MmMapIoSpace.

Syntax

void MmUnmapIoSpace(
  [in] PVOID  BaseAddress,
  [in] SIZE_T NumberOfBytes
);

Parameters

[in] BaseAddress

Pointer to the base virtual address to which the physical pages were mapped.

[in] NumberOfBytes

Specifies the number of bytes that were mapped.

Return value

None

Remarks

If a driver calls MmMapIoSpace during device start-up, it must call MmUnmapIoSpace when it receives a PnP stop-device or remove-device IRP for the same device object.

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
IRQL <=DISPATCH_LEVEL

See also

MmMapIoSpace