Title: Library initialization and versioning

The GDK and GTK headers annotate deprecated APIs in a way that produces compiler warnings if these deprecated APIs are used. The warnings can be turned off by defining the macro GDK_DISABLE_DEPRECATION_WARNINGS before including the gdk.h header.

GDK and GTK also provide support for building applications against defined subsets of deprecated or new APIs. You can define the macro GDK_VERSION_MIN_REQUIRED to specify up to what version you want to receive warnings about deprecated APIs; and the macro GDK_VERSION_MAX_ALLOWED to specify the newest version whose API you want to use. If you attempt to use a function deprecated before the version of GTK specified in GDK_VERSION_MIN_REQUIRED, or a function introduced after the version of GTK specified in GDK_VERSION_MAX_ALLOWED, the compiler will warn you when building your code.