Hi all, I'm in the process to migrate our application from RedHat 5.5 (gcc 4.1.2) to Ubuntu 10.04 (gcc 4.4.3), one regression test is not passing due the fact that lexical_cast is not throwing, this is the line: unsigned int myNumber = boost::lexical_cast<unsigned int>("-123"); I'm using boost 1.40 on both servers. I have noticed that the same executable compiled on Ubuntu 10.04 while on Ubuntu doesn't throw, running it on RH 5.5 throws, so it seems a system library problem. Trying with a simple stringstream, it seems that with the following code: std::stringstream myStream; myStream << "-123"; unsigned int myUInt; myStream >> myUInt; doens't set the fail bit on Ubuntu 10.04, but it does on RedHat 5.5. Does anyone have an idea on what is going on Regards Gaetano Mendola