Marshal.AllocHGlobal Method (IntPtr)

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

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

public static IntPtr AllocHGlobal(
	IntPtr cb
)

Parameters

cb
Type: System.IntPtr

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.

ExceptionCondition
OutOfMemoryException

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.

For example code, see Marshal and AllocHGlobal.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

  • SecurityCriticalAttribute 

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

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