@section @code{vsnprintf}
@findex vsnprintf
-POSIX specification: @url{http://www.opengroup.org/susv3xsh/vsnprintf.html}
+POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/vsnprintf.html}
Gnulib module: vsnprintf or vsnprintf-posix