I have posted a background paper on NaNs on the wiki in the NaNs area. Comments welcome. --- Fred J. Tydeman Tydeman Consulting tydeman at tybor.com Testing, numerics, programming +1 (775) 358-9748 Vice-chair of PL22.11 (ANSI "C") Sample C99+FPCE tests: http://www.tybor.com Savers sleep well, investors eat well, spenders work forever.