src/mscorlib/shared/Interop/Windows/Kernel32/Interop.WriteFile_SafeHandle_IntPtr.cs


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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using Microsoft.Win32.SafeHandles;
using System;
using System.Runtime.InteropServices;

internal partial class Interop
{
    internal partial class Kernel32
    {
        // Note there are two different WriteFile prototypes - this is to use 
        // the type system to force you to not trip across a "feature" in 
        // Win32's async IO support.  You can't do the following three things
        // simultaneously: overlapped IO, free the memory for the overlapped 
        // struct in a callback (or an EndWrite method called by that callback),
        // and pass in an address for the numBytesRead parameter.

        [DllImport(Libraries.Kernel32, SetLastError = true)]
        internal static extern unsafe int WriteFile(SafeHandle handle, byte* bytes, int numBytesToWrite, out int numBytesWritten, IntPtr mustBeZero);
    }
}