CONFIGURING PACKAGES TO WORK WITH GTK ------------------------------------- Compiling a program succesfully against the GTK, GDK, and GLIB libraries can require a large number of command line options to your compiler and linker that are hard to guess correctly. The additional libraries required may, for example, depend on the manner which GTK was configured Several tools are included in this package to make process easier. First, there is the shell script 'gtk-config' (installed in $exec_prefix/bin): Invoking gtk-config ------------------- gtk-config takes the following flags: --version Prints out the version of GTK installed --cflags Prints '-I' flags pointing to the installed header files. --libs Prints out the linker flags necessary to link a program against GTK --prefix[=PREFIX] If PREFIX is specified, overrides the configured value of $prefix. (And of exec-prefix, unless --exec-prefix is also specified) Otherwise, prints out the configured value of $prefix --exec-prefix[=PREFIX] If PREFIX is specified, overrides the configured value of $exec_prefix. Otherwise, prints out the configured value of $exec_prefix Example of using gtk-config --------------------------- Typically, gtk-config will be used within a configure script, as described below. It, however, can also be used directly from the command line to compile a simple program. For example: cc -o simple `gtk-config --cflags` simple.c `gtk-config --libs` This command line might expand to (for example): cc -o simple -I/usr/local/lib/glib/include -I/usr/local/include \ -I/usr/X11R6/include simple.c -L/usr/local/lib -L/usr/X11R6/lib \ -lgtk -lgdk -lglib -lXi -lXext -lX11 -lm Not only is the form using gtk-config easier to type, it will work on any system, no matter how GTK was configured. AM_PATH_GTK ----------- For packages configured using GNU automake, GTK also provides a macro to automate the process of running GTK. AM_PATH_GTK([MINIMUM-VERSION, [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]]]) This macro: * Determines the location of GTK using gtk-config, which is either found in the user's path, or from the environment variable GTK_CONFIG * Tests the installed libraries to make sure that there version is later than MINIMUM-VERSION. (A default version will be used if not specified) * If the required version was found, sets the GTK_CFLAGS variable to the output of `gtk-config --cflags` and the GTK_LIBS variable to the output of `gtk-config --libs`, 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, sets GTK_CFLAGS and GTK_LIBS to empty strings, and executes ACTION-IF-NOT-FOUND. This macro is in file 'gtk.m4' which is installed in $datadir/aclocal. Note that if automake was installed with a different --prefix than GTK, you will either have to manually move gtk.m4 to automake's $datadir/aclocal, or give aclocal the -I option when running it. Configuring a package that uses AM_PATH_GTK ------------------------------------------- Simply make sure that gtk-config is in your path, and run the configure script. Notes: * The directory where the GTK libraries are installed needs to be found by your system's dynamic linker. This is generally done by editing /etc/ld.so.conf and running ldconfig Or by: setting the environment variable LD_LIBRARY_PATH, or, as a last resort, Giving a -R or -rpath flag (depending on your linker) when running configure, for instance: LDFLAGS=-R/usr/home/owen/lib ./configure * You can also specify a gtk-config not in your path by setting the GTK_CONFIG environment variable to the name of the executable * If you move the GTK package from its installed location, you will need either need to modify gtk-config script manually to point to the new location or rebuild GTK. Advanced note: * configure flags --with-gtk-prefix=PREFIX --with-gtk-exec-prefix=PREFIX are provided to override the prefix and exec-prefix that were stored in the gtk-config shell script by GTK's configure. You are generally better off configuring GTK with the right path to begin with. Example of a package using AM_PATH_GTK -------------------------------------- The following shows how to build a simple package using automake and the AM_PATH_GTK macro. The program used here is the testinput.c You should first read the introductory portions of the automake Manual, if you are not already familiar with it. Two files are needed, 'configure.in', which is used to build the configure script: ==configure.in=== dnl Process this file with autoconf to produce a configure script. AC_INIT(testinput.c) AM_INIT_AUTOMAKE(testinput.c, 1.0.0) AC_PROG_CC AM_PROG_CC_STDC AC_PROG_INSTALL AM_PATH_GTK(0.99.5, [LIBS="$LIBS $GTK_LIBS" CFLAGS="$CFLAGS $GTK_CFLAGS"], AC_MSG_ERROR(Cannot find GTK: Is gtk-config in path?)) AC_OUTPUT(Makefile) ================= The only command in this which is not standard for automake is the AM_PATH_GTK() macro. That command does the following: If a GTK version greater than 0.99.5 is found, adds $GTK_LIBS to $LIBS and $GTK_CFLAGS to $CFLAGS. Otherwise, dies with the error message "Cannot find GTK: Is gtk-config in path?" And the 'Makefile.am', which will be used to build the Makefile. == Makefile.am == bin_PROGRAMS = testinput testinput_SOURCES = testinput.c ================= This Makefile.am, says that we are building a single executable, from a single sourcefile 'testinput.c'. Since every program we are building uses GTK we simply added the GTK options to $LIBS and $CFLAGS, but in other circumstances, we might want to specify them on a per-program basis: for instance by adding the lines: testinput_LDADD = $(GTK_LIBS) INCLUDES = $(GTK_CFLAGS) to the Makefile.am. To try this example out, create a new directory, add the two files above two it, and copy the testinput.c file from the gtk/ subdirectory to the new directory. Edit the line: #include "gtk.h" in testgtk.c, to read: #include Now execute the following commands: automake --add-missing aclocal autoconf You now have a package that can be built in the normal fashion ./configure make make install Notes: * If you are converting a package that used a pre-1.0 version of GTK, you should remove the autoconf tests for X. The results of these tests are included in gtk-config and will be added to GTK_LIBS and GTK_CFLAGS by the AM_PATH_GTK macro. Owen Taylor 14 Mar 1997