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Marshal.AllocHGlobal Method (Int32)

Allocates memory from the unmanaged memory of the process.

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

public static IntPtr AllocHGlobal (
	int cb
public static IntPtr AllocHGlobal (
	int cb
public static function AllocHGlobal (
	cb : int
) : IntPtr
Not applicable.



The number of bytes in memory required.

Return Value

An IntPtr to the newly allocated memory. This memory must be released using the Marshal.FreeHGlobal method.

Exception typeCondition


There is insufficient memory to satisfy the request.

AllocHGlobal is one of two memory allocation API methods in the Marshal class. (Marshal.AllocCoTaskMem is the other.) This method exposes the LocalAlloc Win32 API from Kernel32.dll. For additional information about LocalAlloc, see the MSDN Library.


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.

The following code example demonstrates calling the AllocHGlobal method. This code example is part of a larger example provided for the Marshal class.

// Demonstrate how to call GlobalAlloc and 
// GlobalFree using the Marshal class.
IntPtr hglobal = Marshal.AllocHGlobal(100);

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0