On CentOS 4.5 (x86_64); happening on several different machines with libstdc++ and libstdc++-devel v. 3.4.6-8 only one of the i386 or x86_64 versions of libstc++-devel is installed if I yum install libstdc++-devel it will install the x86_64 version and remove the i386 version, but not warn me. Similarly if the i386 version is installed it will install the x86_64 and remove the i386, without warning. But if i remove libstc++-devel (and necessarily gcc-c++), then reinstall with yum install gcc-g++ libstdc++-devel both versions of libstdc++-devel will be installed. Tony Schreiner Biology Department Boston College