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Marshal.DestroyStructure Method

Frees all substructures that the specified unmanaged memory block points to.

Namespace:  System.Runtime.InteropServices
Assembly:  mscorlib (in mscorlib.dll)

public static void DestroyStructure(
	IntPtr ptr,
	Type structuretype


Type: System.IntPtr
A pointer to an unmanaged block of memory.
Type: System.Type
Type of a formatted class. This provides the layout information necessary to delete the buffer in the ptr parameter.


structureType has an automatic layout. Use sequential or explicit instead.

You can use this method to free reference-type fields, such as strings, of an unmanaged structure. Unlike its fields, a structure can be a value type or a reference type. Value-type structures that contain value-type fields (all blittable) have no references whose memory must be freed. The Marshal.StructureToPtr method uses this method to prevent memory leaks when reusing memory occupied by a structure.

DestroyStructure calls the COM SysFreeString function, which, in turn, frees an allocated string.

In addition to DestroyStructure, the Marshal class provides two other memory-deallocation methods: FreeCoTaskMem and FreeHGlobal.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

  • SecurityCriticalAttribute 

    requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, 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.