ZwUnmapViewOfSection function

The ZwUnmapViewOfSection routine unmaps a view of a section from the virtual address space of a subject process.

Syntax

NTSYSAPI NTSTATUS ZwUnmapViewOfSection(
  HANDLE ProcessHandle,
  PVOID  BaseAddress
);

Parameters

ProcessHandle

Handle to a process object that was previously passed to ZwMapViewOfSection.

BaseAddress

Pointer to the base virtual address of the view to unmap. This value can be any virtual address within the view.

Return Value

ZwUnmapViewOfSection returns an NTSTATUS value. Possible return values include:

Return code Description
STATUS_SUCCESS
The routine successfully performed the requested operation.
STATUS_ACCESS_DENIED
The caller does not have access rights to the process object or to the base virtual address of the view.

Remarks

This routine unmaps the entire view of the section that contains BaseAddress from the virtual address space of the specified process—even if BaseAddress does not point to the beginning of the view.

On return from ZwUnmapViewOfSection, the virtual-address region occupied by the view is no longer reserved and is available to map other views or private pages. If the view was also the last reference to the underlying section, all committed pages in the section are decommitted, and the section is deleted.

Note If the call to this function occurs in user mode, you should use the name "NtUnmapViewOfSection" instead of "ZwUnmapViewOfSection".
For calls from kernel-mode drivers, the NtXxx and ZwXxx versions of a Windows Native System Services routine can behave differently in the way that they handle and interpret input parameters. For more information about the relationship between the NtXxx and ZwXxx versions of a routine, see Using Nt and Zw Versions of the Native System Services Routines.

Requirements

   
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 PASSIVE_LEVEL
DDI compliance rules PowerIrpDDis, HwStorPortProhibitedDDIs

See Also

Using Nt and Zw Versions of the Native System Services Routines

ZwMapViewOfSection

ZwOpenSection