Gnulib module: isnan
Portability problems fixed by Gnulib:
isnanwas introduced with C99 and is thus commonly not present on pre-C99 systems.
isnanis not a macro on some platforms: IRIX 6.5, OSF/1 5.1 with gcc, Solaris 11 2011-11.
isnandoes not recognize some NaNs.
isnandoes not recognize some forms of NaNs, such as pseudo-NaNs, pseudo-Infinities, and unnormalized numbers.
isnanimplementations based on it) in GCC 4.0 and later does not recognize pseudo-denormals as NaNs, and similarly for pseudo-zeroes, unnormalized numbers, and pseudo-denormals on ia64.
Portability problems not fixed by Gnulib: