From: Yukihiro Matsumoto Date: 2006-07-29T18:13:04+09:00 Subject: Re: Bug in ruby printf/sprintf Hi,] In message "Re: Bug in ruby printf/sprintf" on Sat, 29 Jul 2006 04:45:13 +0900, "paul.dlug@gmail.com" writes: |That's interesting. I just tried the same on linux (Gentoo) and you're |correct, printf in C behaves the same way there. In Mac OS X (10.4) and |FreeBSD (6.1) it does zero pad it as does perl on all platforms. I |wonder why I haven't hit this before and what the reason for the |difference is. Time to take a look at the doc's for the linux version. From Linux man page printf(3): 0 The value should be zero padded. For d, i, o, u, x, X, a, A, e, E, f, F, g, and G conversions, the converted value is padded on the left with zeros rather than blanks. If the 0 and - flags both appear, the 0 flag is ignored. If a precision is given with a numeric conversion (d, i, o, u, x, and X), the 0 flag is ignored. For other conversions, the behavior is undefined. It's behavior is undefined, so that some fills with zeros and others just ignore. Don't use zero with %s specifier if you want portable behavior. matz.