a GdkWindow
the property to change
the new type for the property. If mode is GDK_PROP_MODE_PREPEND or GDK_PROP_MODE_APPEND, then this must match the existing type or an error will occur.
the new format for the property. If mode is GDK_PROP_MODE_PREPEND or GDK_PROP_MODE_APPEND, then this must match the existing format or an error will occur.
a value describing how the new data is to be combined with the current data.
the data (a guchar * gushort *, or gulong *, depending on format), cast to a guchar *.
Changes the contents of a property on a window.