Marshal.PtrToStringBSTR Method

Allocates a managed String and copies a BSTR string stored in unmanaged memory into it.

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

static String^ PtrToStringBSTR (
	IntPtr ptr
public static String PtrToStringBSTR (
	IntPtr ptr
public static function PtrToStringBSTR (
	ptr : IntPtr
) : String
Not applicable.



The address of the first character of the unmanaged string.

Return Value

A managed string that holds a copy of the native string if the value of the ptr parameter is not a null reference (Nothing in Visual Basic); otherwise, this method returns a null reference (Nothing in Visual Basic).

Only call this method on strings allocated with the unmanaged SysAllocString and SysAllocStringLen functions.

PtrToStringBSTR is useful for custom marshaling or when mixing managed and unmanaged code. Since this method creates a copy of the unmanaged string's contents, you must free the original string as appropriate. This method provides the opposite functionality of Marshal.StringToBSTR.


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.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, 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