Well, I finally found some related -rather old- issues in Bugzilla (glib)<br /><br
/>http://sources.redhat.com/bugzilla/show_bug.cgi?id=6530<br
/>http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=208308<br/>http://sources.redhat.com/bugzilla/show_bug.cgi?id=649<br
/><br/>The last explains why they do not consider it a bug:<br /><br /> ISO C99 requires for %.*s to only write
completecharacters that fit below the<br /> precision number of bytes. If you are using say UTF-8 locale, but
ISO-8859-1<br/> characters as shown in the input file you provided, some of the strings are<br /> not valid UTF-8
strings,therefore sprintf fails with -1 because of the<br /> encoding error. That's not a bug in glibc.<br /><br />It's
clear,though it's also rather ugly, from a specification point of view (we must <br />count raw bytes for the width
field,but also must decode the utf8 chars for finding <br />character boundaries). I guess we must live with that. <br
/><br/>Hernán J. González