<div class="gmail_quote">2010/6/8 Sebastian Redl <span dir="ltr"><<a href="mailto:sebastian.redl@getdesigned.at">sebastian.redl@getdesigned.at</a>></span><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> <div class="im"><br> On Tue, 8 Jun 2010 12:23:03 +0200, Jos� Tom�s Tocino Garc�a<br> <<a href="mailto:theom3ga@gmail.com">theom3ga@gmail.com</a>> wrote:<br> > � � � � cout << myTree.get<float>("sonido.limite", 0.);<br> ><br> </div><div class="im">> If I compile using "g++ -o program testcase1.cpp -I." I get no errors,<br> but<br> > if I add "-Wall", I get:<br> ><br> > ./boost/property_tree/detail/ptree_implementation.hpp: In function �int<br> > main(int, char**)�:<br> > ./boost/property_tree/detail/ptree_implementation.hpp:728: warning:<br> > dereferencing pointer �default_value� does break strict-aliasing rules<br> > /usr/include/boost/optional/optional.hpp:422: note: initialized from<br> here<br> ><br> > What's the problem? It compiles and works properly, but it would be<br> great<br> > to<br> > have a warning-free compilation output.<br> <br> </div>That's really weird, and looks more like a compiler bug to me than a valid<br> warning. For sure, 'default_value' is certainly not initialized within<br> optional.hpp. But then, the strict-aliasing warnings are flow-sensitive and<br> thus emitted during optimization, which means that GCC's internal view of<br> the source could be quite seriously messed up by then.<br> <br> Do you get the warning if you explicitly type the default value correctly,<br> i.e. use '0.f' instead of '0.'?<br> <font color="#888888"><br> Sebastian</font><br></blockquote></div><br>If I use 0.f, I still get the error, but it disappears if I omit the default value. Looks like disabling optimisation (in my code, -O2 was actually used) also makes the error disappear.<br> <br> I think that's what I'm going to do, wraping the call in a try...catch block, so if the value does not exist, I'll manually asign it to the variable.<br> <br> Thanks for your answer.<br clear="all"><br>-- <br>Jos� Tom�s Tocino Garc�a<br>