What is the pkg-config application for ?01.03.25

pkg-config

14 Sep 2024

pkg-config is a tool that originated in Linux to view the meta information about installed libraries. It can be used to know things like:

include path of header files
    link path of library files
    version of library
    etc.

When a library is built or installed, usually a .pc meta file is produced. .pc file contains all meta information such as link path, etc. For pkg-config to work with the library, the .pc file must be placed in the correct search location (PKG_CONFIG_PATH environment variable).
Example use

Say I want to use libpng to work with png images. I install libpng via say homebrew and now want to use it in my project as a library. How can I do that?

First let’s see what version of libpng do I have
    $ pkg-config --modversion libpng
    1.6.43

Ok good. Where can I find the header files for libpng
    $ pkg-config --cflags libpng
    -I/opt/local/include/libpng16 -I/opt/local/include

Nice. What about the path of libraries to link?
    $ pkg-config --libs libpng
    -L/opt/local/lib -lpng16

With these information I can easily use the library with my project like:
gcc pngViewr.c -o pngViewr -I/opt/local/include/libpng16 -I/opt/local/include -L/opt/local/lib -lpng16

or even better:
gcc pngViewr.c -o pngViewr $(pkg-config --libs -cflags libpng)

https://bipinoli.github.io/2024/09/14/pkg-config.html

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What is the pkg-config application for ?01.03.25

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