flt.nan? → true or false

Returns true if flt is an invalid IEEE floating point number.

a = -1.0      #=> -1.0
a.nan?        #=> false
a = 0.0/0.0   #=> NaN
a.nan?        #=> true

Source Code

/*
*  call-seq:
*     flt.nan? -> true or false
*  
*  Returns <code>true</code> if <i>flt</i> is an invalid IEEE floating
*  point number.
*     
*     a = -1.0      #=> -1.0
*     a.nan?        #=> false
*     a = 0.0/0.0   #=> NaN
*     a.nan?        #=> true
*/

static VALUE
flo_is_nan_p(num)
    VALUE num;
{     
   double value = RFLOAT(num)->value;

   return isnan(value) ? Qtrue : Qfalse;
}