Application Binary Interface

In computer software, an application binary interface (ABI) is the interface between two program modules, one of which is often a library or operating system, at the level of machine code. An ABI determines such details as how functions are called and in which binary format information should be passed from one program component to the next, or to the operating system in the case of a system call.

Adhering to ABIs (which may or may not be officially standardized) is usually the job of the compiler, OS or library writer, but application programmers may have to deal with ABIs directly when writing programs in a mix of programming languages, using foreign function call interfaces between them.

ABIs differ from application programming interfaces (APIs), which similarly define interfaces between program components, but at the source code level.

ABIs cover details such as:

A complete ABI, such as the Intel Binary Compatibility Standard (iBCS), allows a program from one operating system supporting that ABI to run without modifications on any other such system, provided that necessary shared libraries are present, and similar prerequisites are fulfilled.

Other ABIs standardize details such as the C++ name mangling,exception propagation, and calling convention between compilers on the same platform, but do not require cross-platform compatibility.

An embedded-application binary interface (EABI) specifies standard conventions for file formats, data types, register usage, stack frame organization, and function parameter passing of an embedded software program, for use with an embedded operating system.

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