Libffi
Encyclopedia
libffi is a foreign function interface
library. It provides a C programming language interface for calling natively compiled functions
given information about the target function
at run time instead of compile time
. It also implements the opposite functionality: libffi can produce a pointer to a function that can accept and decode any combination of arguments defined at run time.
libffi is most often used as a bridging technology between compiled and interpreted
language implementations. libffi may also be used to implement plug-ins, where the plug-in's function signatures are not known at the time of creating the host application.
Notable users include Python
, Dalvik
, F-Script, PyPy
, PyObjC
, RubyCocoa
, JRuby
, Rubinius
, MacRuby
, gcj, GNU Smalltalk
, IcedTea
, Cycript, Pawn, Squeak
, Java Native Access
, Racket, Embeddable Common Lisp
and Mozilla
.
On Mac OS X
libffi is commonly used with BridgeSupport, which provides programming language
neutral descriptions of framework
interfaces, and Nu
which binds direct Objective-C
access from Lisp.
libffi has been widely ported and is released under a MIT license
.
. Gencall was developed by Gianni Mariani, then employed by SGI
, for the purpose of allowing calls to functions by address and creating a call frame for the particular calling convention. Anothony Green refined the idea and extended it to other architectures and calling conventions and open sourcing libffi.
Foreign function interface
A foreign function interface is a mechanism by which a program written in one programming language can call routines or make use of services written in another. The term comes from the specification for Common Lisp, which explicitly refers to the language features for inter-language calls as...
library. It provides a C programming language interface for calling natively compiled functions
Subroutine
In computer science, a subroutine is a portion of code within a larger program that performs a specific task and is relatively independent of the remaining code....
given information about the target function
Subroutine
In computer science, a subroutine is a portion of code within a larger program that performs a specific task and is relatively independent of the remaining code....
at run time instead of compile time
Compile time
In computer science, compile time refers to either the operations performed by a compiler , programming language requirements that must be met by source code for it to be successfully compiled , or properties of the program that can be reasoned about at compile time.The operations performed at...
. It also implements the opposite functionality: libffi can produce a pointer to a function that can accept and decode any combination of arguments defined at run time.
libffi is most often used as a bridging technology between compiled and interpreted
Interpreter (computing)
In computer science, an interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language...
language implementations. libffi may also be used to implement plug-ins, where the plug-in's function signatures are not known at the time of creating the host application.
Notable users include Python
Python (programming language)
Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
, Dalvik
Dalvik virtual machine
Dalvik is the process virtual machine in Google's Android operating system. It is the software that runs the apps on Android phones. Dalvik is thus an integral part of Android, which is typically used on mobile devices such as mobile phones, tablet computers and netbooks. Programs are commonly...
, F-Script, PyPy
PyPy
PyPy is a Python interpreter and JIT compiler. PyPy focuses on speed, efficiency and 100% compatibility with the original CPython interpreter.- Details and motivation :...
, PyObjC
PyObjC
PyObjC is a bidirectional bridge between Python and Objective-C. It allows Python scripts to use and extend existing Objective-C class libraries....
, RubyCocoa
RubyCocoa
RubyCocoa is a Mac OS X framework that provides a bridge between the Ruby and the Objective-C programming languages, allowing the user to manipulate Objective-C objects from Ruby, and vice-versa. It makes it possible to write a Cocoa application completely in Ruby as well as to write an application...
, JRuby
JRuby
JRuby is a Java implementation of the Ruby programming language, being developed by the JRuby team. It is free software released under a three-way CPL/GPL/LGPL license...
, Rubinius
Rubinius
Rubinius is an alternative Ruby programming language implementation created by Evan Phoenix. Based loosely on the Smalltalk-80 Blue Book design, Rubinius seeks to"provide a rich, high-performance environment for running Ruby code."-Goals:...
, MacRuby
MacRuby
MacRuby is an implementation of the Ruby language that runs on the Objective-C runtime and CoreFoundation framework under development by Apple Inc. which "is supposed to replace RubyCocoa". It is based on Ruby 1.9 and uses the high performance Low Level Virtual Machine compiler infrastructure...
, gcj, GNU Smalltalk
GNU Smalltalk
GNU Smalltalk is an implementation of the Smalltalk programming language by the GNU Project.The implementation, unlike other Smalltalk environments, uses text files for program input and interprets the contents as Smalltalk code...
, IcedTea
IcedTea
IcedTea is a build and integration project for OpenJDK launched by Red Hat in June 2007. The initial goal was to make the Java OpenJDK software which Sun Microsystems released as free software in 2007 usable without requiring any other software that is not free software and hence make it possible...
, Cycript, Pawn, Squeak
Squeak
The Squeak programming language is a Smalltalk implementation. It is object-oriented, class-based and reflective.It was derived directly from Smalltalk-80 by a group at Apple Computer that included some of the original Smalltalk-80 developers...
, Java Native Access
Java Native Access
Java Native Access provides Java programs easy access to native shared libraries without using the Java Native Interface. JNA's design aims to provide native access in a natural way with a minimum of effort...
, Racket, Embeddable Common Lisp
Embeddable Common Lisp
Embeddable Common Lisp is a LGPL Common Lisp implementation aimed at producing a small-footprint Lisp system that can be embedded into existing C-based applications...
and Mozilla
Mozilla
Mozilla is a term used in a number of ways in relation to the Mozilla.org project and the Mozilla Foundation, their defunct commercial predecessor Netscape Communications Corporation, and their related application software....
.
On Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
libffi is commonly used with BridgeSupport, which provides programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
neutral descriptions of framework
Software framework
In computer programming, a software framework is an abstraction in which software providing generic functionality can be selectively changed by user code, thus providing application specific software...
interfaces, and Nu
Nu (programming language)
Nu is an interpreted object-oriented programming language, with a Lisp-like syntax, created by Tim Burks as an alternative scripting language to program Mac OS X through its Cocoa application programming interface...
which binds direct Objective-C
Objective-C
Objective-C is a reflective, object-oriented programming language that adds Smalltalk-style messaging to the C programming language.Today, it is used primarily on Apple's Mac OS X and iOS: two environments derived from the OpenStep standard, though not compliant with it...
access from Lisp.
libffi has been widely ported and is released under a MIT license
MIT License
The MIT License is a free software license originating at the Massachusetts Institute of Technology . It is a permissive license, meaning that it permits reuse within proprietary software provided all copies of the licensed software include a copy of the MIT License terms...
.
History
libffi, originally developed by Anthony Green, was inspired by the Gencall library from Silicon GraphicsSilicon Graphics
Silicon Graphics, Inc. was a manufacturer of high-performance computing solutions, including computer hardware and software, founded in 1981 by Jim Clark...
. Gencall was developed by Gianni Mariani, then employed by SGI
Silicon Graphics
Silicon Graphics, Inc. was a manufacturer of high-performance computing solutions, including computer hardware and software, founded in 1981 by Jim Clark...
, for the purpose of allowing calls to functions by address and creating a call frame for the particular calling convention. Anothony Green refined the idea and extended it to other architectures and calling conventions and open sourcing libffi.
Adoption
The libffi library is useful in building a bridge between interpreted and natively compiled code. Some notable users include:- CPythonCPythonCPython is the default, most-widely used implementation of the Python programming language. It is written in C. In addition to CPython, there are two other production-quality Python implementations: Jython, written in Java, and IronPython, which is written for the Common Language Runtime. There...
- the default, most-widely used implementation of the Python programming language uses libffi in the standard ctypes library. - OpenJDKOpenJDKOpenJDK is a free and open source implementation of the Java programming language. It is the result of an effort Sun Microsystems began in 2006...
- the open-source implementation of the Java Platform Standard Edition uses libffi to bridge between the interpreter and native code for Zero-Assembly port - DalvikDalvik virtual machineDalvik is the process virtual machine in Google's Android operating system. It is the software that runs the apps on Android phones. Dalvik is thus an integral part of Android, which is typically used on mobile devices such as mobile phones, tablet computers and netbooks. Programs are commonly...
- Dalvik is the virtual machine which runs the Java platform on Android mobile devices. libffi is used on Android ports for which no custom bridging code has been written. - Java Native AccessJava Native AccessJava Native Access provides Java programs easy access to native shared libraries without using the Java Native Interface. JNA's design aims to provide native access in a natural way with a minimum of effort...
(JNA) - the JNI-free way to call native code from Java. - Ruby-FFI - a Foreign Function Interface extension for Ruby.
- fsbv - Foreign Structure By Value is a foreign function interface library for Common Lisp that extends the standard CFFI package to include support for passing structure arguments by value.
- JSCocoa - call Objective-C code from javascript on Mac OSX and the iPhone (via the libffi-iphone port).
- F-Script - dynamically generate Cocoa classes written in F-Script.
- PyObjCPyObjCPyObjC is a bidirectional bridge between Python and Objective-C. It allows Python scripts to use and extend existing Objective-C class libraries....
- call Objective-C code from Python on Mac OSX. - RubyCocoaRubyCocoaRubyCocoa is a Mac OS X framework that provides a bridge between the Ruby and the Objective-C programming languages, allowing the user to manipulate Objective-C objects from Ruby, and vice-versa. It makes it possible to write a Cocoa application completely in Ruby as well as to write an application...
- call Objective-C code from Ruby on Mac OSX. - Racket - call C code from this popular Scheme implementation (also used as the implementation platform for Paul Graham's new Lisp, Arc).
- gcj - the runtime library for the GNU Compiler for the Java Programming Language uses libffi to handle calls back and forth between interpreted and natively compiled code. gcj is part of the GCC, the GNU Compiler CollectionGNU Compiler CollectionThe GNU Compiler Collection is a compiler system produced by the GNU Project supporting various programming languages. GCC is a key component of the GNU toolchain...
. - MozillaMozillaMozilla is a term used in a number of ways in relation to the Mozilla.org project and the Mozilla Foundation, their defunct commercial predecessor Netscape Communications Corporation, and their related application software....
- libffi is used in the js-ctypes library (previously known as ctypes.jsm) to call C functions within JavaScriptJavaScriptJavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....
code (available in XULRunnerXULRunnerXULRunner is a runtime environment developed by the Mozilla Foundation to provide a common back-end for XUL-based applications. It replaced the Gecko Runtime Environment, a stalled project with a similar purpose....
applications, Firefox extensions etc). - GNU GuileGNU GuileGNU Guile is an interpreter/virtual machine for the Scheme programming language. It was first released in 1993. Guile includes modularized extensions for POSIX system calls, APL array functionality, and others packaged as an object library...
- libffi is used in Guile 1.9.8 and onwards.