StackWalker by Jochen Kalmbach [MVP VC++] and available on codeproject is probably the easiest way to do this. It wraps up all of the details of dealing with the underlying StackWalk64 API.
It's not in the public Qt API, but if you look in
$QTDIR/src/corelib/kernel/qcrashhandler.*
you can see the beginnings of a cross-platform implementation of exactly this.