Mathematical Library Functions                          isnan(3M)



NAME
     isnan - test for NaN

SYNOPSIS
     cc [ flag... ] file... -lm [ library... ]
     #include 

     int isnan(double x);


     c99 [ flag... ] file... -lm [ library... ]
     #include 

     int isnan(real-floating x);


DESCRIPTION
     In C90 mode, the isnan() function tests whether x is NaN.


     In C99 mode, the isnan() macro determines whether its  argu-
     ment  value is NaN. First, an argument represented in a for-
     mat wider than its semantic type is converted to its  seman-
     tic type. The determination is then based on the type of the
     argument.

RETURN VALUES
     Both the isnan() function and macro return non-zero  if  and
     only if x is NaN.

ERORS
     No errors are defined.

WARNINGS
     In C99 mode, the practice of explicitly supplying  a  proto-
     type for isnan() after the line

       #include 



     is obsolete and will no longer work.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:









SunOS 5.11          Last change: 12 Jul 2006                    1






Mathematical Library Functions                          isnan(3M)



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     fpclassify(3M),   isfinite(3M),   isinf(3M),   isnormal(3M),
     math.h(3HEAD), signbit(3M), attributes(5), standards(5)











































SunOS 5.11          Last change: 12 Jul 2006                    2