5 POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/isnan.html}
9 Portability problems fixed by Gnulib:
12 This macro is missing on some platforms:
15 @code{isnan} was introduced with C99 and is thus commonly not present
18 @code{isnan} is not a macro on some platforms:
19 IRIX 6.5, Solaris 11.4.
21 This macro does not work on some platforms:
24 On IRIX 6.5 with @code{cc}, @code{isnan} does not recognize some NaNs.
27 Portability problems not fixed by Gnulib:
30 This macro returns an unspecified result when given noncanonical values
31 such as unnormalized numbers, pseudo-denormals, pseudo-NaNs,
32 pseudo-Infinities, and pseudo-zeroes.