Marshal.FreeBSTR Method

Frees a BSTR using the COM SysFreeString function.

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

public static void FreeBSTR(
	IntPtr ptr
)

Parameters

ptr
Type: System.IntPtr

The address of the BSTR to be freed.

Like Marshal.FreeCoTaskMem and Marshal.FreeHGlobal, you can use this method to deallocate memory. FreeBSTR calls the COM SysFreeString function, which frees memory allocated by any of the following unmanaged methods: SysAllocString, SysAllocStringByteLen, SysAllocStringLen, SysReAllocString, SysReAllocStringLen. You can call unmanaged methods such as these with platform invoke. For details, see Consuming Unmanaged DLL Functions.

.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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