pkgconf

pkgconf is a program which helps to configure compiler and linker flags for development libraries. It is similar to pkg-config from freedesktop.org.

libpkgconf is a library which provides access to most of pkgconf's functionality, to allow other tooling such as compilers and IDEs to discover and use libraries configured by pkgconf.

using pkgconf with autotools

Implementations of pkg-config, such as pkgconf, are typically used with the PKG_CHECK_MODULES autoconf macro. As far as we know, pkgconf is compatible with all known variations of this macro. pkgconf detects at runtime whether or not it was started as 'pkg-config', and if so, attempts to set program options such that its behaviour is similar.

In terms of the autoconf macro, it is possible to specify the PKG_CONFIG environment variable, so that you can test pkgconf without overwriting your pkg-config binary. Some other build systems may also respect the PKG_CONFIG environment variable.

To set the environment variable on the bourne shell and clones (i.e. bash), you can run:

$ export PKG_CONFIG=/usr/bin/pkgconf

comparison of pkgconf and pkg-config dependency resolvers

pkgconf builds an acyclic directed dependency graph. This allows for the user to more conservatively link their binaries -- which may be helpful in some environments, such as when prelink(1) is being used. As a result of building a directed dependency graph designed for the specific problem domain provided by the user, more accurate dependencies can be determined.

Current release versions of pkg-config, on the other hand, build a database of all known pkg-config files on the system before attempting to resolve dependencies, which is a considerably slower and less efficient design. Efforts have been made recently to improve this behaviour.

As of the 1.1 series, pkgconf also fully implements support for Provides rules, while pkg-config does not. pkg-config only provides the --print-provides functionality as a stub. There are other intentional implementation differences in pkgconf's dependency resolver versus pkg-config's dependency resolver in terms of completeness and correctness, such as, for example, how Conflicts rules are processed.

linker flags optimization

As previously mentioned, pkgconf makes optimizations to the linker flags in both the case of static and shared linking in order to avoid overlinking binaries and also simplifies the CFLAGS and LIBS output of the pkgconf tool for improved readability.

This functionality depends on the pkg-config module properly declaring it's dependency tree instead of using Libs and Cflags fields to directly link against other modules which have pkg-config metadata files installed.

Doing so is discouraged by the freedesktop tutorial anyway.

compatibility with pkg-config

I really hate that I have to have this section, I like being a nice person, but we unfortunately have to say this because otherwise we get passive-aggressive people who try to argue with us about what pkg-config compatibility means.

We do not provide bug-level compatibility with pkg-config.

What that means is, if you feel that there is a legitimate regression versus pkg-config, do let us know, but also make sure that the .pc files are valid and follow the rules of the pkg-config tutorial, as most likely fixing them to follow the specified rules will solve the problem.

Additionally, we do not consider pkgconf doing what you tell it to do, in cases for which pkg-config fails to do so, to be a bug.

If, for example, you use environment variables such as PKG_CONFIG_SYSTEM_[INCLUDE|LIBRARY]_PATH and then find yourself surprised that pkgconf is stripping -I and -L flags relating to those paths, it is not a pkgconf problem -- pkgconf is doing exactly what you told it to do.

We will reject bugs like this, and if someone insists on fixing such a non-bug, this constitutes a violation of our Code of Conduct, which may be addressed by banning from this repository.

debug output

Please use only the stable interfaces to query pkg-config. Do not screen-scrape the output from --debug: this is sent to stderr for a reason, it is not intended to be scraped. The --debug output is not a stable interface, and should never be depended on as a source of information. If you need a stable interface to query pkg-config which is not covered, please get in touch.

compiling pkgconf and libpkgconf on UNIX

pkgconf is basically compiled the same way any other autotools-based project is compiled:

$ ./configure
$ make
$ sudo make install

If you are installing pkgconf into a custom prefix, such as /opt/pkgconf, you will likely want to define the default system includedir and libdir for your toolchain. To do this, use the --with-system-includedir and --with-system-libdir configure flags like so:

$ ./configure \
     --prefix=/opt/pkgconf \
     --with-system-libdir=/lib:/usr/lib \
     --with-system-includedir=/usr/include
$ make
$ sudo make install

compiling pkgconf and libpkgconf with Meson (usually for Windows)

pkgconf is compiled using Meson on Windows. In theory, you could also use Meson to build on UNIX, but this is not recommended at this time as it pkgconf is typically built much earlier than Meson.

$ meson setup build -Dtests=false
$ meson compile -C build
$ meson install -C build

There are a few defines such as SYSTEM_LIBDIR, PKGCONFIGDIR and SYSTEM_INCLUDEDIR. However, on Windows, the default PKGCONFIGDIR value is usually overridden at runtime based on path relocation.

pkg-config symlink

If you want pkgconf to be used when you invoke pkg-config, you should install a symlink for this. We do not do this for you, as we believe it is better for vendors to make this determination themselves.

$ ln -sf pkgconf /usr/bin/pkg-config

release tarballs

Release tarballs are available at https://distfiles.dereferenced.org/pkgconf/. Please only use the tarballs from distfiles.dereferenced.org.

contacts

You can report bugs at https://github.com/pkgconf/pkgconf/issues.

There is a mailing list at https://lists.sr.ht/~kaniini/pkgconf.

You can contact us via IRC at #pkgconf at irc.oftc.net.