dlaisnan (l) - Linux Man Pages
dlaisnan: routine i not for general use
NAMEDLAISNAN - routine i not for general use
- LOGICAL FUNCTION
- DOUBLE PRECISION DIN1,DIN2
PURPOSEThis routine is not for general use. It exists solely to avoid over-optimization in DISNAN.
DLAISNAN 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.
- DIN1 (input) DOUBLE PRECISION
DIN2 (input) DOUBLE PRECISION
Two numbers to compare for inequality.