GIO comes with a gio-2.0.pc file that you should use together with pkg-config to obtain the necessary information about header files and libraries. See the pkg-config man page or the GLib documentation for more information on how to use pkg-config to compile your application.

If you are using GIO on UNIX-like systems, you may want to use UNIX-specific GIO interfaces such as GUnixInputStream, GUnixOutputStream, GUnixMount or GDesktopAppInfo. To do so, use the gio-unix-2.0.pc file instead of gio-2.0.pc

Since GIO is based on GObject, you need to call g_type_init() before you can use any GIO functions. If your application uses GTK+, this is already taken care of by gtk_init().