On 19 January 2011 23:27, Nick Stokes wrote: > > Ian, you are right on. The versions are different: > compute node (where gcc is built): /lib64/libc-2.5.so > login node (where gcc is used): /lib64/libc-2.11.2.so > > Jonathan, I looked at the config.logs (attached). Both seem to use gnu. Yes, both your distros have a new enough glibc, so the problem might be simpler: does it make any difference if you define _GNU_SOURCE when compiling? That should ensure uselocale is defined by <locale.h> > When I configure with --enable-clocale=generic it indeed remedies the > issue and g++ works without errors. Are the any serious implications > of not using gnu model? (any performance issues, or anything like that > sort?) The GNU model, which requires glibc 2.3 or later, supports a per-thread locale (via the uselocale function) so that the locale can be changed temporarily by the C++ runtime library without affecting the global process-wide locale. I believe this avoids possible race conditions in multithreaded programs which make use of locales.