ABIcompatible

ABIcompatible describes software components that can interoperate at the binary level without recompilation, by adhering to the same Application Binary Interface (ABI). The ABI defines calling conventions, data type sizes and layouts, alignment, name mangling, and binary interfaces for linked libraries and executables. When two binaries share an identical ABI on the same architecture and operating system, they can be combined, updated, or replaced independently.

Maintaining ABI compatibility means avoiding changes that would alter the binary interface. Changes to function signatures, structure layouts, endianness, or runtime conventions can break ABI compatibility. To minimize disruption, developers use stable ABIs, explicit versioning, and careful packaging practices. Techniques include symbol versioning and the use of opaque data types or handle-based interfaces to hide implementation details. Platform ecosystems often enforce ABI stability across minor releases to support dynamic linking and plugin architectures.

Common contexts for ABI compatibility include shared libraries, plug-in systems, and kernels, where pre-compiled binaries must remain usable as dependencies evolve. Examples include platform-specific ABIs such as the System V AMD64 ABI on Linux and macOS, or the Windows x86-64 calling convention. Language runtimes and compilers typically target a defined ABI to ensure that code produced by one toolchain can run with code produced by another.

Limitations and risks include accidental ABI drift during development, compiler optimizations that affect inlining and alignment, and cross-language interactions requiring careful bridge code. ABIcompatibility contrasts with source compatibility, which concerns source code recompilation rather than binary-level interchange.