UnmanagedCallersOnlyAttribute.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

namespace System.Runtime.InteropServices
{
    /// <summary>
    /// Any method marked with <see cref="UnmanagedCallersOnlyAttribute" /> can be directly called from
    /// native code. The function token can be loaded to a local variable using the <see href="https://docs.microsoft.com/dotnet/csharp/language-reference/operators/pointer-related-operators#address-of-operator-">address-of</see> operator
    /// in C# and passed as a callback to a native method.
    /// </summary>
    /// <remarks>
    /// Methods marked with this attribute have the following restrictions:
    ///   * Method must be marked "static".
    ///   * Must not be called from managed code.
    ///   * Must only have <see href="https://docs.microsoft.com/dotnet/framework/interop/blittable-and-non-blittable-types">blittable</see> arguments.
    /// </remarks>
    [AttributeUsage(AttributeTargets.Method, Inherited = false)]
    public sealed class UnmanagedCallersOnlyAttribute : Attribute
    {
        public UnmanagedCallersOnlyAttribute()
        {
        }

        /// <summary>
        /// Optional. If omitted, the runtime will use the default platform calling convention.
        /// </summary>
        /// <remarks>
        /// Supplied types must be from the official "System.Runtime.CompilerServices" namespace and
        /// be of the form "CallConvXXX".
        /// </remarks>
        public Type[]? CallConvs;

        /// <summary>
        /// Optional. If omitted, no named export is emitted during compilation.
        /// </summary>
        public string? EntryPoint;
    }
}