|Author: RamyaNaidu 07 Aug 2008||Member Level: Silver Points : 2|
|"API" redirects here. For other uses, see API (disambiguation).|
An application programming interface (API) is a set of declarations of the functions (or procedures) that an operating system, library or service provides to support requests made by computer programs.
Language-dependent APIs are available only in a particular programming language. They utilize the syntax and elements of the programming language to make the API convenient to use in this particular context.
Language-independent APIs are written in a way that means they can be called from several programming languages. This is a desired feature for a service-style API which is not bound to a particular process or system and is available as a remote procedure call.
1 API versus ABI
2 Distinction between specification and its implementation
3 Release policies
4 API examples
5 Language bindings and interface generators
6 See also
8 External links
 API versus ABI
An API is typically defined at a higher level (i.e., in terms of a programming language that can be compiled when an application is built, rather than an explicit low level description of how data is laid out in memory). For example, the Linux Standard Base is an ABI (Application Binary Interface), while POSIX is an API.
 Distinction between specification and its implementation
The software that provides the functionality described by an API is said to be an implementation of the API. The API itself is abstract, in that it specifies an interface and the behavior of the identifiers specified in that interface; it does not specify how the behavior may be implemented.
 Release policies
There are two general kinds of API publishing policies that are often encountered:
Some companies protect information on their APIs from the general public. For example, Sony used to make its official PlayStation 2 API available only to licensed PlayStation developers. This enabled Sony to control who wrote PlayStation 2 games. Such control can have quality control benefits and potential license revenue.
Some companies make their APIs freely available. For example, Microsoft makes the Microsoft Windows API public and Apple releases its APIs Carbon and Cocoa so that software can be written for their platform.
 API examples
Below are listed some well-known APIs.
The PC BIOS call interface
Comedi Data Acquisition API
Single UNIX Specification (SUS)
The various Java Platform Edition APIs (Micro, Standard, Enterprise)
ASPI for SCSI device interfacing
Carbon and Cocoa for the Macintosh OS
OpenGL cross-platform 3D graphics API
DirectX for Microsoft Windows
Simple DirectMedia Layer (SDL)
Google Maps API
PayPal Payment Pro
 Language bindings and interface generators
Below are listed some interface generator tools.
SWIG generates interfaces from various languages for Python
F2PY: Fortran to Python interface generator.