the function to call for each node visited. If this function returns TRUE, the traversal is stopped.
the order in which nodes are visited, one of G_IN_ORDER, G_PRE_ORDER and G_POST_ORDER
user data to pass to the function
Deprecated: The order of a balanced tree is somewhat arbitrary. If you just want to visit all nodes in sorted order, use g_tree_foreach() instead. If you really need to visit nodes in a different order, consider using an [n-ary tree][glib-N-ary-Trees].
Calls the given function for each node in the GTree