id summary reporter owner description type status milestone component version severity resolution keywords cc 3610 boost::format copy constructor can create format object in unexpected state. David Ward Samuel Krempp "If I copy construct a new boost::format object, I expect it to be in a (re)useable state. However, the following code throws a boost::io::too_many_args exception { boost::format f(""%d""); std::cout << f % 10 << std::endl; std::cout << f % 10 << std::endl; // format object can be reused boost::format f2(f); std::cout << f2 % 10 << std::endl; // exception raised - new format is not in a valid state for formatting } On inspection of the code, the copy constructor always sets the dumped_ member to false, yet it copies the cur_arg_ from the rhs object. It's hard to see how this behaviour might be desirable. " Bugs closed Boost 1.41.0 format Boost 1.37.0 Problem fixed