5 POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/isnan.html}
9 Portability problems fixed by Gnulib:
12 @code{isnan} was introduced with C99 and is thus commonly not present
15 On IRIX 6.5 with @code{cc}, @code{isnan} does not recognize some NaNs.
17 On NetBSD/i386 and glibc/ia64, @code{isnan} does not recognize some
18 forms of NaNs, such as pseudo-NaNs, pseudo-Infinities, and
21 On i686 and @var{x}86-64, @code{__builtin_isnanl} (and thus
22 @code{isnan} implementations based on it) in GCC 4.0 and later does
23 not recognize pseudo-denormals as NaNs, and similarly for
24 pseudo-zeroes, unnormalized numbers, and pseudo-denormals on ia64.
27 Portability problems not fixed by Gnulib: