Migrating from GTK+ 2.x to GTK+ 3

Only single includes
Do not use deprecated symbols
Use accessor functions instead direct access
GTK+ Modules

There are a number of steps that you can take to prepare your GTK+ 2.x application for the switch to GTK+ 3.

Only single includes

Make sure your program only include the toplevel headers:

    make CFLAGS+="-DG_DISABLE_SINGLE_INCLUDES -DGDK_PIXBUF_DISABLE_SINGLE_INCLUDES -DGTK_DISABLE_SINGLE_INCLUDES"