isnan, has not been explicitly declared

When I use pgi compilation I always say that isnan does not declare, is there a function that does function of isnan

Hi yaoshunyu,

Given “isnan” is not standard, I would suggest you use the Fortran “ieee_is_nan” intrinsic from “ieee_arithmetic”. For example:

% cat isnan.f90
program test
  use, intrinsic :: IEEE_ARITHMETIC
  real :: X = -1.0
  print *, ieee_is_nan(sqrt(X))
end program test
% pgfortran isnan.f90 ; a.out

Hope this helps,

thx,it’s work