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Native interoperability ABI support

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The Application Binary Interface (ABI) is the interface that runtimes and operating systems use to express low-level binary details. Those details can include calling conventions (that is, how parameters are passed and results returned), exception handling, and symbol mangling. The list that follows contains the names of languages, runtimes, and even general technologies that you might use when looking for guidance on interoperability.

C

The C language represents a stable ABI across all platforms where .NET is supported. In general, C is the assumed target for .NET interop APIs and is the recommended target language for most interop scenarios.

In .NET 7+, LibraryImportAttribute provides source-generated support for calling C functions. If you're targeting .NET 6 or earlier, use DllImportAttribute. For more information, see Interop best practices.

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C++

The C++ language has no defined ABI across all .NET supported platforms and the most popular C++ compiler implementations (that is, MSVC, clang, and GCC). This lack of a consistent ABI makes it difficult to target directly.

The recommended way to interoperate with C++ is to export functions marked with extern "C" and call them as C functions.

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COM and IUnknown

The COM and IUnknown ABI was defined to align with the C language. It was specifically designed to support object-oriented programming, similar to C++, but to provide a stable ABI. .NET has a deep history with COM and IUnknown, and as this ABI was originally designed to align with C, it's supported on all .NET platforms.

In .NET 5+, low-level, cross-platform, IUnknown lifetime support is provided by ComWrappers. In .NET 8+, GeneratedComInterfaceAttribute and GeneratedComClassAttribute provide source generated C# projections. If you're targeting versions prior to .NET 5, you must use the built-in COM interop system, and this support is limited to Windows.

The WinRT platform represents an evolution of the COM and IUnknown ABI. Support for this is provided by the CsWinRT toolkit and is built upon ComWrappers.

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Java Virtual Machine (JVM) based languages

The Java Virtual Machine (JVM) defines a foreign function interface (FFI) in C to interoperate with other platforms. Interoperability between .NET and Java can be achieved via this interface.

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Swift

The Swift programming environment has a well-defined stable ABI that is supported in .NET. In .NET 9+, specific APIs that support interop with Swift can be found under the System.Runtime.InteropServices.Swift namespace.

Objective-C

The Objective-C language follows the C language's ABI and is supported in .NET. In .NET 8+, specific APIs that support interop with Objective-C can be found under the System.Runtime.InteropServices.ObjectiveC namespace.

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Python

The reference implementation of the Python run-time, CPython, defines a foreign function interface (FFI) in C to interoperate with other platforms. Interoperability between .NET and Python can be achieved via this interface.

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golang

The Go programming language is not supported for in-process interoperability. The Go runtime imposes requirements on being hosted in a process with another runtime. Specifically, that requirement is the use of the SA_ONSTACK flag on threads that run signal handlers. These requirements are not currently met by .NET.

The recommended way to interoperate with golang is to use a golang-hosted process and communicate through an inter-process communication mechanism.

ARM64EC

The ARM64EC ABI is not supported.