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mxIsNaN (C and Fortran)

Determine whether input is NaN (Not-a-Number)

C Syntax

#include "matrix.h"
bool mxIsNaN(double value);

Fortran Syntax

#include "fintrf.h"
integer*4 mxIsNaN(value)
real*8 value



Double-precision, floating-point number to test


Logical 1 (true) if value is NaN (Not-a-Number), and logical 0 (false) otherwise.


Call mxIsNaN to determine whether value is NaN. NaN is the IEEE® arithmetic representation for Not-a-Number. A NaN is obtained as a result of mathematically undefined operations such as

  • 0.0/0.0

  • Inf-Inf

The system understands a family of bit patterns as representing NaN. NaN is not a single value; it is a family of numbers that MATLAB® (and other IEEE-compliant applications) uses to represent an error condition or missing data.


See these examples in matlabroot/extern/examples/mx:

See these examples in matlabroot/extern/examples/refbook:

Version History

Introduced before R2006a