5 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/log2f.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 3.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, IRIX 6.5, Solaris 9,
20 This function is only provided as a macro on some platforms: