Marshal.StringToCoTaskMemUni Method

Copies the contents of a managed String to a block of memory allocated from the unmanaged COM task allocator.

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

public static IntPtr StringToCoTaskMemUni (
	string s
public static IntPtr StringToCoTaskMemUni (
	String s
public static function StringToCoTaskMemUni (
	s : String
) : IntPtr
Not applicable.



A managed string to be copied.

Return Value

An integer representing a pointer to the block of memory allocated for the string, or 0 if a null string was supplied.

Exception typeCondition


The s parameter exceeds the maximum length allowed by the operating system.


There is insufficient memory available.

StringToCoTaskMemUni is useful for custom marshaling or for use when mixing managed and unmanaged code. Since this method allocates the unmanaged memory required for a string, always free the memory by calling Marshal.FreeCoTaskMem. This method provides the opposite functionality of Marshal.PtrToStringUni. The characters of the string are copied as Unicode characters.


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 Millennium Edition, 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