Compiling GLib Applications
3
GLib Library

# Compiling GLib Applications

How to compile your GLib application

## Compiling GLib Applications on UNIX

To compile a GLib application, you need to tell the compiler where to find the GLib header files and libraries. This is done with the pkg-config utility.

The following interactive shell session demonstrates how pkg-config is used (the actual output on your system may be different):

    $ pkg-config --cflags glib-2.0
     -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include
    $ pkg-config --libs glib-2.0
     -L/usr/lib -lm -lglib-2.0

See the pkg-config website for more information about pkg-config.

If your application uses or GObject features, it must be compiled and linked with the options returned by the following pkg-config invocation:

    $ pkg-config --cflags --libs gobject-2.0

If your application uses modules, it must be compiled and linked with the options returned by one of the following pkg-config invocations:

    $ pkg-config --cflags --libs gmodule-no-export-2.0
    $ pkg-config --cflags --libs gmodule-2.0

The difference between the two is that gmodule-2.0 adds `--export-dynamic` to the linker flags, which is often not needed.

The simplest way to compile a program is to use the "backticks" feature of the shell. If you enclose a command in backticks (not single quotes), then its output will be substituted into the command line before execution. So to compile a GLib Hello, World, you would type the following:

    $ cc `pkg-config --cflags --libs glib-2.0` hello.c -o hello

Deprecated GLib functions are annotated to make the compiler emit warnings when they are used (e.g. with gcc, you need to use the -Wdeprecated-declarations option). If these warnings are problematic, they can be turned off by defining the preprocessor symbol GLIB_DISABLE_DEPRECATION_WARNINGS by using the commandline option `-DGLIB_DISABLE_DEPRECATION_WARNINGS`

The older deprecation mechanism of hiding deprecated interfaces entirely from the compiler by using the preprocessor symbol G_DISABLE_DEPRECATED is still used for deprecated macros, enumeration values, etc. To detect uses of these in your code, use the commandline option `-DG_DISABLE_DEPRECATED`.

The recommended way of using GLib has always been to only include the toplevel headers `glib.h`, `glib-object.h`, `gio.h`. Starting with 2.32, GLib enforces this by generating an error when individual headers are directly included.

Still, there are some exceptions; these headers have to be included separately: `gmodule.h`, `glib-unix.h`, `glib/gi18n-lib.h` or `glib/gi18n.h` (see the Internationalization section), `glib/gprintf.h` and `glib/gstdio.h` (we don't want to pull in all of stdio).