[SOLVED] What is the purpose of the last parameter?

[edbarx]

I answered my own question.

Could anyone explain to me what is the purpose of the parameter within single quotation marks and what it does? I am assuming it is a call to pkg-config with those paramaters.

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gcc -o gtkprog gtkprog.c `pkg-config --libs --cflags gtk+-2.0`

Using:

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pkg-config --libs --cflags gtk+-2.0
-pthread -I/usr/include/gtk-2.0 -I/usr/lib/x86_64-linux-gnu/gtk-2.0/include -I/usr/include/gio-unix-2.0/ -I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/libpng12 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng12 -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/freetype2 -lgtk-x11-2.0 -lgdk-x11-2.0 -lpangocairo-1.0 -latk-1.0 -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lpangoft2-1.0 -lpango-1.0 -lgobject-2.0 -lglib-2.0 -lfontconfig -lfreetype

So, if my logic serves me right, this command parameter is a neat replacement for this litany of libraries to be used in the compilation process.

Correct me if I am wrong.

[saulgoode]

For the most part you are correct, however, it is more than just a simple insertion of the libraries and includes into the command line. pkg-config is part of GNU autotools and it resolves the dependencies of the packages dynamically within the compiler environment at compile time. In your example, it does this by starting with /usr/lib/pkgconfig/gtk+-2.0.pc and recursively checking all of the other packages specified.