Several compilers have an generic intrinsic function ISNAN(): interface logical function isnan(x) real, intent(in) :: x end function isnan end interface
Example for compilers implementing it: ifort, g95, sunf95, sgi. Example for a program using it: http://www.libatoms.org/ Note: Fortran 2003 has IEEE_IS_NAN() in the module IEEE_ATRITHMETIC; the isnan implementation should follow the Fortran 2003 standard. -- Summary: Implement vendor-specific ISNAN() intrinsic function Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: enhancement Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: burnus at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32979