B. Package tools

If you are creating a software package that uses the GiNaC library, setting the correct command line options for the compiler and linker can be difficult. The pkg-config utility makes this process easier. GiNaC supplies all necessary data in ‘ginac.pc’ (installed into /usr/local/lib/pkgconfig by default). To compile a simple program use (6)

g++ -o simple `pkg-config --cflags --libs ginac` simple.cpp

This command line might expand to (for example):

g++ -o simple -lginac -lcln simple.cpp

Not only is the form using pkg-config easier to type, it will work on any system, no matter how GiNaC was configured.

For packages configured using GNU automake, pkg-config also provides the PKG_CHECK_MODULES macro to automate the process of checking for libraries

PKG_CHECK_MODULES(MYAPP, ginac >= MINIMUM_VERSION, 
                  [ACTION-IF-FOUND],
                  [ACTION-IF-NOT-FOUND])

This macro:

• Determines the location of GiNaC using data from ‘ginac.pc’, which is either found in the default pkg-config search path, or from the environment variable PKG_CONFIG_PATH.
• Tests the installed libraries to make sure that their version is later than MINIMUM-VERSION.
• If the required version was found, sets the MYAPP_CFLAGS variable to the output of pkg-config --cflags ginac and the MYAPP_LIBS variable to the output of pkg-config --libs ginac, and calls ‘AC_SUBST()’ for these variables so they can be used in generated makefiles, and then executes ACTION-IF-FOUND.
• If the required version was not found, executes ACTION-IF-NOT-FOUND.