I'd like to use pkg-config to change the include dirs for a package, but it looks like it doesn't accept any options.

After issuing the following command:

pkg-config --cflags ImageMagick -fopenmp -DMAGICKCORE_HDRI_ENABLE=0 -DMAGICKCORE_QUANTUM_DEPTH=16 -I/usr/include/x86_64-linux-gnu/ImageMagick-6 -I/usr/include/ImageMagick-6

...it instantly fails right at the first cflag option:

Unknown option -fopenmp

Is this a normal behavior? How can I make it work?

PS: Using Debian Jessie.

1 Answer 1


pkg-config outputs flags intended to be used with a compiler or linker. Typically you’d use it like this:

gcc $(pkg-config --cflags ImageMagick) …

You can’t use the pkg-config command to change the paths used by a given package. The paths are defined in the corresponding .pc file, e.g. /usr/lib/x86_64-linux-gnu/pkgconfig/ImageMagick.pc. To customize that, the safest option is to copy that file somewhere else, modify it as appropriate, and specify the path to the file using the PKG_CONFIG_PATH environment variable.

Note that if you built the ImageMagick libraries yourself, the build should have produced a valid .pc file for you. You also shouldn’t use .pc files to specify options such as -fopenmp; those shouldngo in your build command, in your makefile or in the CPPFLAGS, CFLAGS or CXXFLAGS environment variables (or makefile variables).

  • Thanks, It wasn't clear at first glance. In fact, I'm trying to compile a program that uses the imagemagick libraries, but some of the headers can be found in a different location (that's why I'm trying to change the path in particular). Unfortunately, the build doesn't producing any .pc files, and I have no idea how make make search for that header file in a another directory (nor how the .pc syntax works). Commented Apr 13, 2017 at 14:07
  • I recommend asking another question explaining what your end goal is, proceeding in this way is probably barking up the wrong tree! Commented Apr 13, 2017 at 14:17
  • That's what I'm going to do, thanks again for your time! Commented Apr 13, 2017 at 14:19

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