5 POSIX specification: @url{https://pubs.opengroup.org/onlinepubs/009695399/functions/ecvt.html}
9 Portability problems fixed by Gnulib:
13 Portability problems not fixed by Gnulib:
16 This function is missing on some platforms:
17 FreeBSD 6.0, NetBSD 9.0, Android 9.0.
19 This function is not declared on some platforms:
22 This function is marked as ``legacy'' in POSIX@. Better use @code{sprintf}