Variant isn't the only data structure where the actual type stored is not known at compile time and therefore unavailable to the debugger to show to the user. You yourself pointed out the others. Every good programmer of which I know is cognizant of the technique of casting the variable or memory area, from within a debugger, to the actual type so that the debugger shows the value. Are you saying it should be up to Boost to tell the programmer about this technique ? I am not saying it might not be helpful, but I do not think it belongs in the documentation as a general rule since the technique is universal to other similar situations, and not to just one or two Boost libraries.
I agree that it should not be in the Boost documentation. However it *is* something to know and everybody has learnt it at a particular moment. It's one of those tips. Especially for 'difficult' (like templated) datastructures, I can image the number of trees hiding the forrest can be very large. To be short: the boost website could have pointers to good related sites (like for debugging) or have a couple of pages of its own that handle these Tips 'n' Tricks. (PS: I'm fairly new to Boost too, so my appologies if my terminology is off.) agb