SYNOPSIS
 LOGICAL FUNCTION
 DLAISNAN(DIN1,DIN2)
 DOUBLE PRECISION DIN1,DIN2
PURPOSE
This routine is not for general use. It exists solely to avoid overoptimization in DISNAN.DLAISNAN checks for NaNs by comparing its two arguments for inequality. NaN is the only floatingpoint value where NaN != NaN returns .TRUE. To check for NaNs, pass the same variable as both arguments.
A compiler must assume that the two arguments are
not the same variable, and the test will not be optimized away. Interprocedural or wholeprogram optimization may delete this test. The ISNAN functions will be replaced by the correct Fortran 03 intrinsic once the intrinsic is widely available.
ARGUMENTS
 DIN1 (input) DOUBLE PRECISION

DIN2 (input) DOUBLE PRECISION
Two numbers to compare for inequality.