Pkg-config
Encyclopedia
pkg-config is computer software that provides a unified interface for querying installed libraries
for the purpose of compiling
software from its source code
. pkg-config was originally designed for Linux
but is now also available for the various BSD
s, Microsoft Windows
, Mac OS X
, and Solaris.
It outputs various information about installed libraries. This information may include:
, deb
, or other binary packaging system), a .pc file should be included and placed into a directory with other .pc files (the exact directory is dependent upon your system and outlined in the pkg-config man page). This file has several entries.
These entries typically contain a list of dependent libraries that programs using the package also need to compile. Entries also typically include the location of header file
s, version information and a description.
Here is an example .pc file for libpng
:
prefix=/usr/local
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${exec_prefix}/include
Name: libpng
Description: Loads and saves PNG files
Version: 1.2.8
Libs: -L${libdir} -lpng12 -lz
Cflags: -I${includedir}/libpng12
This file demonstrates how libpng informs that its libraries can be found in /usr/local/lib and its headers in /usr/local/include, that the library name is libpng, and that the version is 1.2.8. It also gives the additional linker flags that are needed to compile code that uses this library.
Here is an example of usage of pkg-config while compiling:
gcc -o test test.c $(pkg-config --libs --cflags libpng)
Library (computer science)
In computer science, a library is a collection of resources used to develop software. These may include pre-written code and subroutines, classes, values or type specifications....
for the purpose of compiling
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
software from its source code
Source code
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
. pkg-config was originally designed for Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
but is now also available for the various BSD
Berkeley Software Distribution
Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...
s, Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
, 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...
, and Solaris.
It outputs various information about installed libraries. This information may include:
- Parameters for CC (programming language)C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
or C++C++C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
compilerCompilerA compiler is a computer program that transforms source code written in a programming language into another computer language... - Parameters for linker
- Version of the package in question
Synopsis
When a library is installed (likely automatically through the use of an RPMRPM Package Manager
RPM Package Manager is a package management system. The name RPM variously refers to the .rpm file format, files in this format, software packaged in such files, and the package manager itself...
, deb
Deb (file format)
deb is the extension of the Debian software package format and the most often used name for such binary packages. Like the "Deb" part of the term Debian, it originates from the name of Debra, erstwhile girlfriend and now ex-wife of Debian's founder Ian Murdock.Debian packages are also used in...
, or other binary packaging system), a .pc file should be included and placed into a directory with other .pc files (the exact directory is dependent upon your system and outlined in the pkg-config man page). This file has several entries.
These entries typically contain a list of dependent libraries that programs using the package also need to compile. Entries also typically include the location of header file
Header file
Some programming languages use header files. These files allow programmers to separate certain elements of a program's source code into reusable files. Header files commonly contain forward declarations of classes, subroutines, variables, and other identifiers...
s, version information and a description.
Here is an example .pc file for libpng
Libpng
libpng is the official Portable Network Graphics reference library . It is a platform-independent library that contains C functions for handling PNG images...
:
prefix=/usr/local
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${exec_prefix}/include
Name: libpng
Description: Loads and saves PNG files
Version: 1.2.8
Libs: -L${libdir} -lpng12 -lz
Cflags: -I${includedir}/libpng12
This file demonstrates how libpng informs that its libraries can be found in /usr/local/lib and its headers in /usr/local/include, that the library name is libpng, and that the version is 1.2.8. It also gives the additional linker flags that are needed to compile code that uses this library.
Here is an example of usage of pkg-config while compiling:
gcc -o test test.c $(pkg-config --libs --cflags libpng)