slaisnan(l) - Linux man page

Name

SLAISNAN - routine i not for general use

Synopsis

LOGICAL FUNCTION

SLAISNAN(SIN1,SIN2)

REAL

SIN1,SIN2

Purpose

This routine is not for general use. It exists solely to avoid over-optimization in SISNAN.
SLAISNAN checks for NaNs by comparing its two arguments for inequality. NaN is the only floating-point 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 whole-program optimization may delete this test. The ISNAN functions will be replaced by the correct Fortran 03 intrinsic once the intrinsic is widely available.

Arguments

SIN1 (input) REAL

SIN2 (input) REAL Two numbers to compare for inequality.