Language binding

In computing, a binding from a programming language to a library or operating system service is an application programming interface (API) providing glue code to use that library or service in a particular programming language.

Binding generally refers to a mapping of one thing to another. In the context of software libraries, bindings are wrapper libraries that bridge two programming languages so that a library written for one language can be used in another language.^[1] Many software libraries are written in system programming languages such as C or C++; in order to use these libraries from another (usually higher-level) language such as Java, Common Lisp, Python or Lua, a binding to the library must be created in that language, possibly requiring the recompilation of the language's code depending on the amount of modification necessary.^[2] However, most languages offer an interface to foreign functions, such as Python's and OCaml's ctypes, and Embeddable Common Lisp's cffi and uffi.^[3][4][5]

For example, Python bindings are used when an already existing C library written for some purpose is to be used from Python. Another example is libsvn, which is written in C and provides an API for accessing Subversion; in order to access Subversion from within Java code, libsvnjavahl can be used, which depends on libsvn being installed and acts as a bridge between the Java programming language and libsvn, thus providing an API that invokes functions from libsvn to do the real work.^[6]

Software reuse is a major motivation for creating library bindings, rather than reimplementing the library in several languages. Another is the impossibility of implementing certain algorithms efficiently in high-level languages.

See also

• Application programming interface (API)
• Application Binary Interface (ABI)
• Calling convention
• Common Language Infrastructure – .NET cross-language cross-platform Object Model
• Comparison of application virtual machines
• COM – Microsoft Windows only cross-language Object Model
• CORBA – Common Object Request Broker Architecture, cross language cross platform object model
• DCOM – Distributed COM, extension making COM able to work in networks
• Embedded SQL
• Foreign function interface
• Freedesktop.org D-Bus – open cross language cross platform Object Model
• Name mangling
• SWIG – open-source interfaces bindings generator from many languages to many languages
• Portable object – cross language cross platform Object Model definition
• Porting
• XPCOM – Mozilla applications cross-platform Component Object Model
• Wrapper function

References

1. "Appendix A. Creating a language binding for cairo". Cairographics.org. Retrieved 2014-04-02.
2. "Standards, APIs, Interfaces and Bindings". Acm.org. Retrieved 2014-04-02.
3. "15.17. ctypes — A foreign function library for Python". Python v2.7.6 documentation. Docs.python.org. Retrieved 2014-04-02.
4. Jason Hickey; Anil Madhavapeddy; Yaron Minsky (2013). "Real Worl OCaml, Chapter 19. Foreign Function Interface". realworldocaml.org. Retrieved 2015-07-19.
5. "Introduction - CFFI User Manual". Common-lisp.net. Retrieved 2014-04-02.
6. "Subversion JavaHL FAQ". Subclipse.tigris.org. 2013-06-18. Retrieved 2014-04-02.

External links

• JTC1/SC22/WG11 - Binding Techniques, an ISO standard for language bindings
• What is a language binding?