🌟 NativeInvoke

High-performance, source-generated P/Invoke

NativeInvoke is a modern, zero-overhead, generics-capable P/Invoke generator for .NET.
It uses Roslyn source generation to enforce blittable, function-pointer based, lazy-loaded native bindings - without the runtime overhead of DllImport.

You write clean interfaces.
NativeInvoke generates the unsafe bits.

---

🚀 Quick Installation

Install the NuGet package:

dotnet add package NativeInvoke

Or edit your .csproj (followed by dotnet restore):

<ItemGroup>
    <PackageReference Include="NativeInvoke" Version="1.2.0"/>
</ItemGroup>

---

🧠 Why NativeInvoke?

Feature	Benefit
Source-generated	Zero runtime overhead
Function pointers	Faster than DllImport
Lazy-loading support	Load symbols/functions only when needed
Interface-based	Fully mockable for testing
Generics support	Use generics in P/Invoke
No static pollution	Clean public API surface
.NET 9 Lock support	Modern, allocation-free synchronization

• Cross-platform and AOT/JIT-friendly.
• No DllImport.
• No delegate allocation.
• No runtime dependencies.
• No marshalling.
• No reflection.
• No dynamic codegen (dynamic IL).
• Just pure compile-time generation glue.

---

🛠 Requirements

• C# 14 / .NET 9 or later
• Unsafe code enabled (<AllowUnsafeBlocks>true</AllowUnsafeBlocks>)
• Roslyn source generators enabled (default in SDK-style projects)

---

✨ Example Usage

Slightly verbose example to play a beep sound on Windows (without Console.Beep):

1. Define your native interface

global using NativeInvoke; // Import our attributes in your project

using BOOL = int; // Win32 BOOL is 4-bytes (0=false, 1=true)
using DWORD = uint; // double-word

#if NET6_0_OR_GREATER
[System.Runtime.Versioning.SupportedOSPlatform("windows")] // Optional (for clarity)
#endif
public interface IKernel32<TBool> // Generics are supported!
  where TBool : unmanaged
{
  [NativeImportMethod("Beep")] // Optional; Use this attribute if you want to load a different name/ordinal,
                               // or override a calling convention per function (defaults to platform-specific).
  TBool Boop(DWORD frequency, DWORD duration);

  [NativeImportMethod(null)] // Use null or empty string to skip generation.
  void IgnoreMe();
}

2. Expose it via a static partial property

The property can be nested anywhere you want (class/struct/interface/record), and you can use any accessibility level you need - the generator will match your declaration.

public static partial class Win32
{
  // Specify native library name.
  // Optionally set the default calling convention, name prefix/suffix, or whether to use eager/lazy loading.
  [NativeImport("kernel32", Lazy = true)]
  public static partial IKernel32<BOOL> Kernel32 { get; }
}

3. Call it like a normal .NET API

See Example project for more.

Win32.Kernel32.Boop(600u, 300u);

Under the hood, NativeInvoke generates:

• A nested sealed __Impl class implementing your (generic) interface
• Static (readonly) function pointer fields (delegate* unmanaged)
• Lazy or eager symbol resolution (NativeLibrary)
• A clean property implementation using the field keyword
• Thread-safe lazy initialization using .NET 9 Lock type

All without touching your container type.

---

💡 Future/Experiments (ToDo list)

• Support C# 9 / .NET 5 and later via #if; current source generator is relying on C# 14 features and .NET 9 API
• Add support for loading symbol from numeric ordinal (ushort)
• Implement default symbol name prefix and suffix
• Switch to typeof(CallConv*) for future-proofed calling conventions (MemberFunction, Swift, etc.)
• Use IndentedTextWriter for source-code generation
• Append Guid to generated fields (to prevent name collisions for overloaded functions)
• Make unit tests
• Explore micro-optimization: IL weaver via Fody, replace interface dispatch and DllImport calls with calli

---

🙏 Contributing

PRs, issues, and ideas are welcome.
NativeInvoke is built for developers who want maximum performance without sacrificing clean API design.

---

💖 Support

If you like this or you are using this in your project, consider:

• Becoming a ⭐ 🤩
• Spreading the word

---

📄 License

MIT - do whatever you want, just don't blame me if you calli into oblivion.