Check this thread: Diskussion about memory profiler… [developer.qt.nokia.com]
There are several tools and it depends on the platform…

Valgrind [valgrind.org]

That depens on the platform :-) (see noted thread above)

Grrrr. I keep forgetting to put down platform information.

Qt 4.7/Mac OS X 10.6.5

cazador7907, Valgrind should be ok for you then.

Valgrind also has GUI written in Qt4 called Valkyrie [valgrind.org]

There is also a nice visualizer for the massif (one of the valgrind tools) output called massif-visualizer [gitorious.org].

By the by – I have had good success using Boost::Graph and Qt together. This might be overkill for what you need, but it’s the best I’ve found.

I’ve not done any OSX development at all, but I’ve also had good success with simple tools like dmalloc, DUMA, and mpatrol.

I wrote an (IMNSHO) incredibly awesome one about ten years ago, but it breaks badly on C++ templates so it never got released. Someday I will have time to figure out how to rewrite it to make it work again…