Export (0) Print
Expand All
Expand Minimize

Marshal.DestroyStructure Method

Frees all substructures pointed to by the specified unmanaged memory block.

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

[SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
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 reference type. Value-type structures containing value-type fields (all blittable) have no references whose memory must be freed. StructureToPtr uses this method to prevent memory leaks when reusing memory occupied by a structure.

DestroyStructure calls the SysFreeString COM API method, which in turn frees an allocated string. For additional information about SysFreeString, see the MSDN Library.

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


This method uses SecurityAction.LinkDemand to prevent it from being called from untrusted code; only the immediate caller is required to have SecurityPermissionAttribute.UnmanagedCode permission. If your code can be called from partially trusted code, do not pass user input to Marshal class methods without validation. For important limitations on using the LinkDemand member, see Demand vs. LinkDemand.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

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

.NET Compact Framework

Supported in: 3.5

XNA Framework

Supported in: 3.0, 2.0

Community Additions

© 2014 Microsoft