is-nan

function

Library: Floating point number support (OMFLOAT)
Import : omfloat.xmd

Returns: A value of true when x is NaN; otherwise, a value of false.

Declaration

export external switch function is-nan value float x

Purpose

Use is-nan to test a floating point number to determine if it is not a number (NaN). This function returns a switch value of true ("x" is NaN) or false. is-nan provides the only reliable means of determining whether a variable contains a NaN value.

The following "contrived" sample uses is-nan to check for a value that is not a number (NaN). When such a value is found, the message "Error, result is not a number." is displayed.

  import "omfloat.xmd" unprefixed
  process
      local float x initial {3}
      local stream y initial {"A"}
      local float result
      set result to (x / y) 
  
      do when is-nan result
          output "Error, result is not a number. %n"
          halt
      done
  ; Output: "Error, result is not a number."

Other Library Functions