I asked this question a year or two ago on the list. Has anyone come up with a good way to dump template metaprogramming information at compile time? I'd like to be able to do this both in a "print" sense (compiler warnings) and an "error" sence (compiler abort). I hacked something together last week that sort of does the job. There's a print<Message, FileLine> class that has a constructor with an unused variable declared. gcc gives a nice warning with -Wall. I also have some hacked macros to pass file and line number information to the printer. The printer will dump a warning if its constructor is ever instantiated. The use of all this appears in my last post in the "Named Template Parameters" thread. But this is really terrible. I don't like it much so I'm hoping someone else has a better solution. In particular, it's almost useless if there are any errors in the code because compilation will stop before instantiation happens. Unfortunately, this is _exactly_ the case where one really wants to get this information and figure out what's causing the compiler abort. I know this is useful functionality, practically required for any large metaprogramming project. I'd like to see if Boost can make something really good. -Dave