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: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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