Any reason why printf() does not support formats with thousands separator?

$SUBJ says it all - I've recently discovered that a format such as %'.2f" results in this: php -r "printf(\"%'.2f\", 23232323.237);" 23232323.237000 I know that number_format() will do the same, but I am given the format spec as an interface, I would need to try to parse it and then decide whether to use printf() or number_format(). -- Per Jessen, Zürich (19.9°C) http://www.hostsuisse.com/ - virtual servers, made in Switzerland.