LD_LIBRARY_PATH and alternative

I compiled and installed the most recent version of Armadillo library, and tested a sample program here. Both compilation and build went well, but when I tried to run the resulted program, I got an error message saying that the library files were not found. I followed the suggestions found here and created a new file " /etc/ld.so.conf.d/local.conf" which has only one line of contents:

/usr/local/lib64

Which seems to do the trick and,from my understanding, is better than have a line in my .bashrc for "LD_LIBRARY_PATH".

==================== EDITED SEPT. 24, 2010 ==============================

Now I realized that every time a new library is installed, I need to run "sudo sudo ldconfig".