snprintf(3) and friends async-signal safety?

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

Hi list,

While working on my msgfmt thingy for dd(1) [1], I found that 
snprintf(3) gets used in summary(), which is a function that can be 
called via the SIGINFO handler.

Unfortunately, I am not quite certain of what I read; a quick look at 
snprintf(3) code in libc/stdio makes me believe that the function is 
_not_ async signal safe (it is not listed in signal(7) either), but is 
still used in as-is in dd(1).

Question is: is it really safe to use it in a signal handler inside 
NetBSD?

[1] 
http://mail-index.netbsd.org/tech-userlevel/2010/12/04/msg004195.html

--
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost