Assembly: mscorlib (in mscorlib.dll)
The following example demonstrates how to implement the SetHandle method. To reliably set a handle to a specified pre-existing handle, you must ensure that the allocation of the native handle and the subsequent recording of that handle within a SafeHandle object is atomic. Any failure between these operations (such as a thread abort or out of memory exception) will result in the native handle being leaked. The code example that follows shows how reliability can be achieved using a constrained execution region.
<StructLayout(LayoutKind.Sequential)> _ Structure MyStruct Public m_outputHandle As IntPtr End Structure 'MyStruct NotInheritable Class MySafeHandle Inherits SafeHandle ' Called by P/Invoke when returning SafeHandles Public Sub New() MyBase.New(IntPtr.Zero, True) End Sub Public Function AllocateHandle() As MySafeHandle ' Allocate SafeHandle first to avoid failure later. Dim sh As New MySafeHandle() RuntimeHelpers.PrepareConstrainedRegions() Try Finally Dim myStruct As New MyStruct() NativeAllocateHandle(myStruct) sh.SetHandle(myStruct.m_outputHandle) End Try Return sh End Function
Windows 98, Windows 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 .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.