Seen in FreeBSD 6.1. printf "%010f" and printf "%010a", applied to NaN, Inf, or -Inf, pad with zeroes. Should pad with spaces instead. [1] http://article.gmane.org/gmane.comp.lib.gnulib.bugs/10051 [2] http://article.gmane.org/gmane.comp.lib.gnulib.bugs/10055