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MemoryMappedFile.OpenExisting Method (String, MemoryMappedFileRights, HandleInheritability)

Opens an existing memory-mapped file that has the specified name, access rights, and inheritability in system memory.

Namespace:  System.IO.MemoryMappedFiles
Assembly:  System.Core (in System.Core.dll)

[SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
public static MemoryMappedFile OpenExisting(
	string mapName,
	MemoryMappedFileRights desiredAccessRights,
	HandleInheritability inheritability


Type: System.String
The name of the memory-mapped file to open.
Type: System.IO.MemoryMappedFiles.MemoryMappedFileRights
One of the enumeration values that specifies the access rights to apply to the memory-mapped file.
Type: System.IO.HandleInheritability
One of the enumeration values that specifies whether a handle to the memory-mapped file can be inherited by a child process. The default is None.

Return Value

Type: System.IO.MemoryMappedFiles.MemoryMappedFile
A memory-mapped file that has the specified characteristics.


mapName is an empty string.


mapName is null.


desiredAccessRights is not a valid MemoryMappedFileRights enumeration value.


inheritability is not a valid HandleInheritability enumeration value.


The requested access is invalid for the memory-mapped file.


The file specified for mapName does not exist.

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.