There are plenty of logging/trace systems for letting your program output data or strings or state as it runs. Most of these let you print arbitrary strings which you can view live or after your program runs.
I noticed an ad here on SO for Smartinspect which seems to take this to a higher level, giving stack traces for each log, fancier options like plotting graphs and data values which change over time, and a lot of polish to the basic idea of a simple list of output text strings.
Since I use C++, Smartinspect won't even work for me.
A little googling finds tons of logging frameworks, but nothing that seems to do anything more than text dumps. Are their fancier tools (similar to Smartinspect?) that do more? Commercial or open source is fine, and multiplatform is a big plus.