I have a number of programs I wrote on Centos 5 (x86_64) and for one of the programs I do ldd programX linux-vdso.so.1 => (0x00007fff2cb86000) libpthread.so.0 => /lib64/libpthread.so.0 (0x0000003528600000) libm.so.6 => /lib64/libm.so.6 (0x0000003527e00000) libxml2.so.2 => /usr/lib64/libxml2.so.2 (0x0000003531400000) libz.so.1 => /usr/lib64/libz.so.1 (0x0000003528a00000) libc.so.6 => /lib64/libc.so.6 (0x0000003527a00000) /lib64/ld-linux-x86-64.so.2 (0x0000003527600000) libdl.so.2 => /lib64/libdl.so.2 (0x0000003528200000) On C6 I do the same thing and the numbers in (Y) might change but everything else is the same for libraries. Is it safe to assume then that if I switch to C6 and recompile my program and then put the C6 version on all my C5 systems (updates that kind of thing) that everything will be compatible and run just fine. Is that the case? Thanks, Jerry _______________________________________________ CentOS mailing list CentOS@xxxxxxxxxx http://lists.centos.org/mailman/listinfo/centos