Simon King wrote: > I get the following error message: > `/usr/local/sage-2.8.5.1/spkg/build/ntl-5.4.1.p5/src/src/small/src' > ./InitSettings: /usr/lib64/libstdc++.so.6: version `GLIBCXX_3.4.9' not > found (required by ./InitSettings) This simply means that there is a disparity between the version of libstdc++ that you linked InitSettings with versus the one that is being found at runtime. You need to tell the dynamic linker (man ld.so) the location of the libstdc++ that corresponds to the gcc version used to compile and link the app, because right now it's finding the system one in /usr/lib64 which is too old. Normally you do this with LD_LIBRARY_PATH but there are other ways. Symbol versioning allows one library file to contain multiple versions of a symbol, which allows for backward but *not* forward compatibility. In other words, the library version at runtime can be newer than the one that the app was linked with but never older. For the details on libstdc++ versioning, see <http://gcc.gnu.org/onlinedocs/libstdc++/abi.html>. Brian
