Marshal.StringToHGlobalAuto(String) Method

Definition

Namespace:

System.Runtime.InteropServices

Assemblies:

netstandard.dll, System.Runtime.InteropServices.dll

Source:

Marshal.Unix.cs

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

C#

public static IntPtr StringToHGlobalAuto(string? s);

Parameters

s

String

A managed string to be copied.

Returns

IntPtr

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

Exceptions

OutOfMemoryException

There is insufficient memory available.

Examples

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.

C++

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;
}

Remarks

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.

This method copies embedded null characters, and includes a terminating null character.

Applies to

See also

• PtrToStringAuto(IntPtr, Int32)