AllocHGlobal Method (Int32)
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Marshal.AllocHGlobal Method (Int32)


Allocates memory from the unmanaged memory of the process by using the specified number of bytes.

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

public static IntPtr AllocHGlobal(
	int cb


Type: System.Int32

The required number of bytes in memory.

Return Value

Type: System.IntPtr

A pointer to the newly allocated memory. This memory must be released using the Marshal.FreeHGlobal method.

Exception Condition

There is insufficient memory to satisfy the request.

AllocHGlobal is one of two memory allocation methods in the Marshal class. (Marshal.AllocCoTaskMem is the other.) This method exposes the Win32 LocalAlloc function from Kernel32.dll.

When AllocHGlobal calls LocalAlloc, it passes a LMEM_FIXED flag, which causes the allocated memory to be locked in place. Also, the allocated memory is not zero-filled.

Legacy Code Example

The following example demonstrates calling the AllocHGlobalmethod. 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);

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

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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