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Marshal.StringToHGlobalAuto Method

Copies the contents of a managed String into unmanaged memory, converting into ANSI format if required.

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

public static IntPtr StringToHGlobalAuto(
	string s
)

Parameters

s
Type: System.String
A managed string to be copied.

Return Value

Type: System.IntPtr
The address, in unmanaged memory, to where the string was copied, or 0 if s is null.

ExceptionCondition
OutOfMemoryException

There is insufficient memory available.

StringToHGlobalAuto is useful for custom marshaling or for use when mixing managed and unmanaged code. Because this method allocates the unmanaged memory required for a string, always free the memory by calling FreeHGlobal. This method provides the opposite functionality of Marshal.PtrToStringAuto.

The following example demonstrates how to convert the contents of a managed String class to unmanaged memory and then dispose of the unmanaged memory when done.


using namespace System;
using namespace System::Runtime::InteropServices;

int main()
{
    // Create a managed string.
    String^ managedString = "Hello unmanaged world (from the managed world).";

    // Marshal the managed string to unmanaged memory.
    char*  stringPointer = (char*) Marshal::StringToHGlobalAuto(managedString).ToPointer();

    // Pass the string to an unmanaged API.

    // Always free the unmanaged string.
    Marshal::FreeHGlobal(IntPtr(stringPointer));

    return 0;
}


.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.

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