If you don't pass enough arguments to a boost::format you get this: "boost::too_few_args: format-string refered to more arguments than were passed" Unfortunately there is, as far as I can tell, no way to figure out where the error happened, other than building a debug version of your app and breaking into the debugger on that error. Needless to say that can be very inconvenient. Would it be possible to fix boost::format (which, by the way, is IMHO one of the most wonderful of all the Boost libraries!!) so that its exceptions carry a little more information about their origins (e.g., embedding the format-string itself in the message)? Thank you. Michael Drumheller Boeing Phantom Works Mathematics and Engineering Analysis 425.373.2703 michael.drumheller@boeing.com This email may contain proprietary information. If you are not the intended recipient please delete it and notify the sender that you received it in error.