TreeStore behavior with -malign-double

[Bryan Silverthorn <bsilvert arlut utexas edu>]

I've attached a small test case (TreeViewTest.cc) that breaks when 
compiled with -malign-double, using gtkmm-2.4.11 and 2.8.8 under RHEL 
and FC5 respectively on i386:

"
$ g++ TreeViewTest.cc `pkg-config --cflags --libs gtkmm-2.4` -o TreeViewTest
$ ./TreeViewTest
hidden data is stored correctly.

$ g++ -malign-double TreeViewTest.cc `pkg-config --cflags --libs 
gtkmm-2.4` -o TreeViewTest
$ ./TreeViewTest
hidden data has gone missing!
"

To summarize: TreeStore columns with custom data types do not correctly 
store their values. I'm assuming that gtk+ and gtkmm were not compiled 
with -malign-double, and that the problem is therefore a direct result 
of the binary compatibility issues introduced by -malign-double.

So this issue is probably more of a (potentially quite time-wasting) 
gotcha than a bug per se, but it would be nice if it wasn't an issue at 
all---or was at least documented and/or checked for at either compile or 
run time.

--
Bryan Silverthorn <bsilvert arlut utexas edu>

// TreeViewTest.cc
// simple demonstration of confusing TreeStore behavior;
// compare when compiled with and without -malign-double

#include <string>
#include <iostream>
#include <gtkmm.h>

using namespace std;

class DerivedTreeView : public Gtk::TreeView
{
	public:
		DerivedTreeView()
		{
			// attach store to view
			Glib::RefPtr<Gtk::TreeStore> store = Gtk::TreeStore::create(_columns);

			this->set_model(store);
			this->append_column("Text", _columns.text);

			// add a row of data
			Gtk::TreeModel::iterator rowiter = store->append();

			(*rowiter)[_columns.text] = "row of data";
			(*rowiter)[_columns.hidden] = new string("stored correctly.");

			// make sure that the hidden data was stored
			string* hidden = rowiter->get_value(_columns.hidden);

			if(hidden)
				cout << "hidden data is " << *hidden << "\n";
			else
				cout << "hidden data has gone missing!\n";
		}

	private:
		struct _ColumnsRecord : public Gtk::TreeModelColumnRecord
		{
			_ColumnsRecord()
			{
				this->add(text);
				this->add(hidden);
			}

			Gtk::TreeModelColumn<Glib::ustring> text;
			Gtk::TreeModelColumn<string*> hidden;
		};

		_ColumnsRecord _columns;
};

int main(int argc, char** argv)
{
	Gtk::Main gtk(argc, argv);

	Gtk::Window window;
	DerivedTreeView tree;

	window.add(tree);

	tree.show();
	window.show();
}