[gtkada] How to make the mouse cursor invisible?

[Pascal]

Hello, how to make the mouse cursor invisible?
GTK 2.24 documentation says:

gdk_cursor_new ()
GdkCursor *         gdk_cursor_new                      (GdkCursorType cursor_type);
Creates a new cursor from the set of builtin cursors for the default display. See gdk_cursor_new_for_display().
To make the cursor invisible, use GDK_BLANK_CURSOR.

But while GDK_BLANK_CURSOR is present in GdkCursorType enum type (GDK_BLANK_CURSOR = -2), it isn't present in Gdk_Cursor_Type from package Gdk.Cursor!

Does exist an another way to make the mouse cursor invisible?

Thanks for your answers, Pascal.
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