The DC-API library uses the pkg-config system to help the building of applications. For every backend, two pkg-config modules are available: dcapi-<backend>-client for building client applications and dcapi-<backend>-master for building master applications. During compilation, the pkg-config --cflags <module> command gives the list of compiler directives (like include file locations) that have to be passed to the compiler whenever one of the DC-API headers is referenced in a source file. During linking, the pkg-config --libs <module> command will return the list of libraries and linker options required to link the application with DC-API. If you have built DC-API from source and have installed it at a non-standard location (i.e. not under /usr or /usr/local), you may have to set the PKG_CONFIG_PATH environment variable to point to the directory where the .pc files are located in order to pkg-config to find them.